• Korean Journal of Materials Research
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• v.27 no.11
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• pp.603-608
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• 2017

$Si_3N_4$ is a ceramic material attracting attention in many fields because of its excellent abrasion resistance. In addition, Ti and TiAl alloys are metals used in a variety of high temperature environments, and have attracted much attention because of their high strength and high melting points. Therefore, study of the interface reaction between $Si_3N_4/Ti$ and $Si_3N_4/TiAl$ can be a useful practice to identify phase selection and diffusion control. In this study, $Si_3N_4/Ti_5Si_3+TiN/TiN/Ti$ diffusing pairs were formed in the $Si_3N_4/Ti$ interfacial reaction and $Si_3N_4/TiN(Al)/Ti_3Al/TiAl$ diffusion pathway was identified in the $Si_3N_4/TiAl$ interfacial reaction. The diffusion layers of the interface reactions were identified and, to investigate the kinetics of the diffusion layer, the integrated diffusion coefficients were estimated.

• Journal of Life Science
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• v.15 no.4 s.71
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• pp.542-547
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• 2005

Hypersensitivity of cells lacking Brcal to DNA interstrand .ross-link (ICL) agents such as cisplatin and mitomycin C(MMC) implicates the important role of Brcal in cellular response following ICL treatment. Brca1 plays an essential role in DNA double-strand break (DSB) repair through homologous recombination (HR)-dependent and -independent process. Recently, our group has been reported that Brca1 involves in cellular ICL response through HR-dependent repair process (Yun J. et at., Oncogene 2005). In this report, the involvement of Brca1 protein in HR-independent repair process is examined using isogenic $p53^{-/-}\;and\;p53^{-/-}\;Brcal^{-/-}$ mouse embryonic fibroblast (MEF) and psoralen cross-linked reporter reactivation assay. Brcal-deficient MEFs showed significantly low HR-independent repair activity compare to Brca1-proficient MEFs. Hypersensitivity to MMC and ICL reporter repair activity were restored by the reconstitution of Brca1 expression. Interestingly, MEFs expressing exon 11-deleted isoform of Brca1 $(Brca1^{\Delta11/\Delta11})$ showed high resistance to MMC and ICL reporter repair activity comparable to Brca1-reconstituted MEFs. Taken together, these results suggest that Brca1 involves in ICL repair through not only HR-dependent process but also HR-independent process using N-terminal RINC finger domain or C-terminal BRCT domain rather than exon 11 region which mediate interaction with Rad50.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.7B
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• pp.659-667
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• 2009

Mobile Ad-hoc Network consists of mobile nodes without immobile base station. In mobile ad-hoc network, network cutting has occurred frequently in node because of energy restriction and frequent transfer of node. Therefore, it requires research for certain techniques that react softly in topology alteration in order to improve reliability of transmission path. This paper proposes path selection techniques to consider mobility of node that respond when search path using AOMDV routing protocol. As applying proposed techniques, We can improve reliability and reduce re-searching number of times caused by path cutting.

• Clean Technology
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• v.22 no.1
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• pp.35-44
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• 2016

In this study, a computational chemistry methodology called as molecular modeling was been applied to explain several experiment results mechanistically. The reaction chosen for this study was to remove carbon dioxide, known as a primary greenhouse gas, by an epoxide via the carbon dioxide fixation to produce carbonates. This reaction inherently needs the use of catalysts because it has a significantly high activation barrier (55~59 kcal/mol). Among various types of catalysts, we studied in zeolitic imidazolate framework 90 (ZIF-90)/ionic liquid immobilized ZIF-90 (IL-ZIF-90), polystyrene-supported quaternized ammonium salt, KI/KI-glycine, and dimethylethanolamine (DMEA). First, probable reaction pathways were proposed based on calculated energetics by computational chemistry. The energetics was then used for the thermodynamic interpretation on the activity of catalysts. In the case of ZIF-90/IL-ZIF-90 and KI/KI-glycine, IL-ZIF-90 and KI-glycine showed better yields compared to their counterparts. The calculation proposed interesting results that it is not from the lowering of activation energy but from the unstable intermediates of ZIF-90 and KI-glycine. For DMEA, the calculated activation energy was ~42 kcal/mol, much lower than that of the non-catalytic reaction. A possible reaction pathway was located to confirm the interaction between −NH group from ammonium and oxygen from epoxide for polystyrene-supported quaternized ammonium salt.

• Clean Technology
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• v.26 no.4
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• pp.311-320
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• 2020

In this study, the photocatalytic degradation of rhodamine B (RhB), methyl orange (MO) and methylene blue (MB) was carried out under visible light irradiation using CdS and CdZnS/ZnO photocatalysts prepared by a simple precipitation method. This study focused on examining the effect of physicochemical properties of dye and photocatalyst on the reaction pathway of photocatalytic degradation. The prepared photocatalysts were characterized by XRD, UV-vis DRS and XPS. Both the CdS and CdZnS/ZnO photocatalysts exhibit an excellent absorption in the visible light and the UV light regions. It was observed that the photocatalytic degradation of MO proceeds via the same reaction mechanism on both the CdS and CdZnS/ZnO photocatalysts. However, the photocatalytic degradation of RhB and MB was found to proceed through a different reaction pathway on the CdS and CdZnS/ZnO catalysts. It is interesting to note that MB dimer was formed on the CdS catalyst at the beginning of the photocatalytic reaction, while the MB monomer was degraded during the overall photocatalytic reaction on CdZnS/ZnO. The above results may be mainly ascribed to the difference of band edge potential of the conduction band in the CdS and CdZnS/ZnO semiconductors and the adsorption property of dye on the catalysts.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.6 no.6
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• pp.943-950
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• 2002

Real time strategy game is a computer game genre of Playing with human or computer opponents in real time It differs from turn-type computer games in the game process method. Turn type games, such as chess, allow only one Player to move at a time. Real time strategy games allow two or more Players to move simultaneously. Therefore, in real time strategy computer games, the game components' movement plans must be calculated very quickly in order to not disturb other processes such as gathering resources, building structures, and combat activities. There are many approaches, which can reduce the amount of memory required for calculating path, search space, and reactive time of components. (or units). However, existing path finding algorithms tend to concentrate on achieving optimal Paths that are not as important or crucial in real time strategy game. This Paper introduces Dynamic Heuristic Af(DHA*) algorithm which is capable of reducing search space and reactive time of game units and compares with A* algorithm using static heuristic weighting.

• KIISE Transactions on Computing Practices
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• v.21 no.2
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• pp.101-108
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• 2015

This paper presents the implementation of a system that recommends empirical best routes based on classification of large trajectory data. As many location-based services are used, we expect the amount of location and trajectory data to become big data. Then, we believe we can extract the best empirical routes from the large trajectory repositories. Large trajectory data is clustered into similar route groups using Hadoop MapReduce framework. Clustered route groups are stored and managed by a DBMS, and thus it supports rapid response to the end-users' request. We aim to find the best routes based on collected real data, not the ideal shortest path on maps. We have implemented 1) an Android application that collects trajectories from users, 2) Apache Hadoop MapReduce program that can cluster large trajectory data, 3) a service application to query start-destination from a web server and to display the recommended routes on mobile phones. We validated our approach using real data we collected for five days and have compared the results with commercial navigation systems. Experimental results show that the empirical best route is better than routes recommended by commercial navigation systems.

• Proceedings of the KSEG Conference
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• 2004.03a
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• pp.12001-12049
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• 2004

암석의 풍화과정은 화학적인 변질, 물리적인 분해 및 생물학적인 작용으로 나뉘어 진다. 풍화에 영향을 주는 요소는 기후, 조성광물의 종류 및 구조, 절리와 단층, 열수변질작용과 광화작용, 염기성 및 산성암맥과 지형 등이다. 또한 암석의 풍화는 성인에 따라 다양한 양상으로 진행되는데 이는 암석을 이루고 있는 각각 광물들이 열역학적인 반응경로가 서로 다르고, 이에 수반되는 물리적인 풍화진행속도가 차이가 있으며, 암석의 균질성, 투수성 등이 암종별로 다양하기 때문이다. 현장에서 암석의 풍화정도는 조성광물의 변질과 분해정도를 육안 등으로 정성적으로 판단하고 분류하는 것이 일반적이다. (중략)

• Proceedings of the KOR-KST Conference
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• 1995.12a
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• pp.111-124
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• 1995

첨단 교통 체계(Intelligent Transport Systems)의 중요한 요소인 첨단 교통 관리 체계(Advanced Traffic Management Systems)의 성공 여부는 교통정보를 어떻게 제공하고 통제하는데 의존하다. 즉, 정보 제공 방식과 이데 대한 운전자의 반응을 정확하게 파악하고 예측하여야 ITS를 성공적으로 구축할 수 있다. 이 논문에서는 동적 차량 길잡이 장치의 효용성을 평가하기 위한 확률적 통행배정모형을 개발하는 것이다. 개발된 통행배정모형은 운전자의 동적행태조정(Dynamic Behavioural Adjustment)을 명백하게 확솔 과정(Stochastic Process)으로 표현하여 기존의 모형에 비해 통해자들의 행태를 더욱 실제적으로 반영한다. 특히, 각 통행자들에게 K개의 최소경로시간을 제공해줌으로 인하여 통행자의 노선선택에 대한 선택폭을 증가시켜준다. 통행경로의 선택폭의 증가는 쟁점으로 대두되는 문제(교통항제소에서는 차량 길잡이 보유 운전자에게 체계최적(System Optimum)와 이용자최적(User Equilibrium)중 어떠한 원칙하에 교통정보를 제공하여야 하는가에 대한 해결 방안이다. 왜냐하면 만약 교통급제소에서 운전자에게 통행정보를 체계 최상을 하기 위해 정보를 제공하고자 하면, 길잡이 장착 운전자는 더 이상 제공된 정보를 따르지 않고 자기 스스로의 경에 의해 이용자 최상을 달성하고자 할 것이다. 이 논문의 목적은 이러한 복잡한 통행자의 경로선택행위를 반영하는 확률적 평형 통행 배정 모형을 여러가지 통계기법을 도입하여 개발하는 것이다.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2006.06a
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• pp.81-108
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• 2006

기존 모바일 광고에 대한 연구는 광고에 대한 현황과 시사점에 대한 연구, 새로운 광고 표현 형태에 대한 탐색적 실험연구, 모바일 광고의 효과 및 장애요인 등에 대한 제한적인 연구에 국한되어 왔다. 실제로 현 시점에서 모바일 광고 기법들에 대한 체계적이고 실증적인 분류와 실제 각각의 광고 형태별 적용가능 분야에 대한 분석 연구는 없었다. 따라서 현재까지 등장한 모바일 광고 기법을 종합하여 재분류하고 광고 형태별 적용 분야에 대한 연구가 필요하다고 본다. 본 연구에서는 메시지 타입, 타겟팅, Delivery유형에 따라 분류한 모바일 광고의 기존연구를 바탕으로 실재 모바일 광고 대행사에서 사용되어지는 광고 상품을 Text, Icon, Media Contents형태로 구분하고 정보제공, 거래유도, 반응유도 및 빈도 그리고 경로 연계라는 측면에서 새롭게 구성을 시도하였다. 또한 광고 메시지 경로에 대한 각자의 광고 기법에 대한 MAP를 그려 실제적이고 실증적인 모바일 광고 체계를 발견하는데 그 의의가 있다.