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An Efficient and Spam-Robust Proximity Measure Between Communication Entities

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Journal of Computer Science & Technology 2013年第2期28卷 394-400页

作者： joo Hyuk Jeon Jihwan Song Jeong Eun Kwon Yoon joon Lee man Ho park Myoung Ho Kim Department of Computer Science Korea Advanced Institute of Science and Technology Biz Solution Team SK Telecom Information Technology R&D Center Mobile Communication Convergence Research Team Electronics and Telecommunications Research Institute

Electronic communication service providers are obliged to retain communication data for a certain amount of time by their local laws. The retained communication data or the communication logs are used in various applications such as crime detection, viral marketing, analytical study, and so on. many of these applications rely on effective techniques for analyzing communication logs. In this paper, we focus on measuring the proximity between two communication entities, which is a fundamental and important step toward further analysis of communication logs, and propose a new proximity measure called ESP （Efficient and Spam-Robust Proximity measure）. Our proposed measure considers only the （graph- theoretically） shortest paths between two entities and gives small values to those between spam-like entities and others. Thus, it is not only computationally efficient but also spam-robust. By conducting several experiments on real and synthetic datasets, we show that our proposed proximity measure is more accurate, computationally efficient and spam-robust than the existing measures in most cases.

关键词： proximity closeness spam electronic communication

Early expressions of hypoxia-inducible factor 1alpha and vascular endothelial growth factor increase the neuronal plasticity of activated endogenous neural stem cells after focal cerebral ischemia

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Neural Regeneration Research 2014年第9期9卷 912-918页

作者： Seung Song Jong-Tae park joo Young Na man-Seok park Jeong-Kil Lee Min-Cheol Lee Hyung-Seok Kim Department of Forensic Medicine Chonnam National University Medical School Department of Neurology Chonnam National University Medical School Department of Neurosurgery Chonnam National University Medical School Department of Pathology Chonnam National University Medical School

Endogenous neural stem cells become ＂activated＂ after neuronal injury, but the activation sequence and fate of endogenous neural stem cells in focal cerebral ischemia model are little known. We evaluated the relationships between neural stem cells and hypoxia-inducible factor-1α and vascular endothelial growth factor expression in a photothromobotic rat stroke model using immunohistochemistry and western blot analysis. We also evaluated the chronological changes of neural stem cells by 5-bromo-2′-deoxyuridine（BrdU） incorporation. Hypoxia-inducible factor-1α expression was initially increased from 1 hour after ischemic injury, followed by vascular endothelial growth factor expression. Hypoxia-inducible factor-1α immunoreactivity was detected in the ipsilateral cortical neurons of the infarct core and peri-infarct area. Vascular endothelial growth factor immunoreactivity was detected in bilateral cortex, but ipsilateral cortex staining intensity and numbers were greater than the contralateral cortex. Vascular endothelial growth factor immunoreactive cells were easily found along the peri-infarct area 12 hours after focal cerebral ischemia. The expression of nestin increased throughout the microvasculature in the ischemic core and the peri-infarct area in all experimental rats after 24 hours of ischemic injury. Nestin immunoreactivity increased in the subventricular zone during 12 hours to 3 days, and prominently increased in the ipsilateral cortex between 3–7 days. Nestin-labeled cells showed dual differentiation with microvessels near the infarct core and reactive astrocytes in the peri-infarct area. BrdU-labeled cells were increased gradually from day 1 in the ipsilateral subventricular zone and cortex, and numerous BrdU-labeled cells were observed in the peri-infarct area and non-lesioned cortex at 3 days. BrdU-labeled cells rather than neurons, were mainly co-labeled with nestin and GFAP. Early expressions of hypoxia-inducible factor-1α and vascular endothelial gr

关键词： nerve regeneration brain ischemia neural stem cell neural precursor cell hypoxia-inducible factor 1α vascular endothelial growth factor microenvironment photothrombosis neural regeneration

Geometric Properties of Ribs and Fans of a Bézier Curve

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Journal of Computer Science & Technology 2006年第2期21卷 279-283页

作者： joo-Haeng Lee Hyungjun park Electronics and Telecommunications Research Institute Daejeon 305-350 Korea Chosun University Gwangju 501-759 Korea

Ribs and fans are interesting geometric entities that are derived from a given Bézier curve or surface based on the recent theory of rib and fan decomposition. In this paper, we present some of new geometric properties of ribs and fans for a Bézier curve including composite fans, rib-invariant deformation, and fan-continuity in subdivision. We also give some examples for the presented properties.

关键词： geometric algorithm Bézier curve composite fan rib-invariance fan-continuity

Effect of CaF2 content in refining slag on formation behavior of spinel inclusion in Ni-Cr-V-alloyed special steel

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Journal of Iron and Steel Research International 2018年第2期25卷 157-163页

作者： Jae-hong Shin joo-hyun park Department of Materials Engineering Hanyang UniversityAnsan 426-791 Korea

The influence of CaF2 content on the formation behavior of spinel inclusions in the Ni-Cr-V-alloyed special steel was presented. The spinel was not formed at CaF2 content lower than 10 wt%. However, it was formed at early stage when the CaF2 content was greater than 30 wt%, followed by a modification to the aluminosilicate-type inclusions. Because the slag was saturated by MgO, the activity of MgO was unity irrespective of CaF2 content in the slag. Thus, Mg was transferred from slag to metal phase. Mg transferred to molten steel reacted with Al2O3-rich inclusions to form ***2O3 spinel. However, the spinel inclusion was modified to aluminosilicate-type inclusions by the reaction with Si and Ca transferred from slag to molten steel about 2-3 h later.

关键词： Spinel inclusion Refining slag CaF2 content Ni-Cr-V-alloyed special steel

Effect of polyethylene glycol on electrochemically deposited trivalent chromium layers

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中国有色金属学会会刊：英文版 2009年第4期19卷 819-823页

作者： joo-Yul LEE man KI M Sik-Chol KWON Department of Surface Technology Korea Institute of Materials Science

The structural characteristics of the trivalent chromium deposits and their interfacial behavior in the plating solution with and without polyethylene glycol molecules were observed by using various electrochemical methods such as cyclic voltammetry,open circuit potential transition,electrochemical impedance spectroscopy,scanning electron microscopy and X-ray photoelectron *** is shown that the polyethylene glycol molecules make the reductive current density lower in the trivalent chromium plating system and promote a hydrogen evolution reaction through their adsorption on the electrode *** the trivalent chromium layer formed from the polyethylene glycol-containing solution has somewhat higher density of cracks on its surface and results in a lower film resistance,lower polarization resistance,and higher capacitance in a corrosive *** is also revealed that the formation of chromium carbide layer is facilitated in the presence of polyethylene glycol,which means easier electrochemical codeposition of chromium and carbon,not single chromium deposition.

关键词：聚乙二醇电沉积层三价铬扫描电子显微镜电化学阻抗谱电极表面电化学方法乙二醇溶液

Evaluation of lubrication performance of crank pin bearing in a marine diesel engine

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Friction 2018年第4期6卷 464-471页

作者： Suk man MOON Yong joo CHO Tae Wan KIM School of Mechanical Engineering Pusan National University Department of Mechanical Engineering Pukyong National University

In this study, the lubrication performance of the crank pin bearing in a marine two–stroke diesel engine is evaluated to investigate the adhesional failure on the crank pin bearing. A numerical algorithm for the lubrication analysis considering motion analysis of the crank pin system is developed. The film pressure and thickness for three clearances and three lubricant temperatures are calculated. The results show that the lubricant temperature has a higher effect on film thickness than clearance. In terms of the film parameter, the operating condition that can result in solid–solid contact is investigated. We also suggest the desirable operating conditions of clearance and lubricant temperature to prevent the solid–solid contact.

关键词： crank pin bearing film thickness lubricant film parameter diesel engine

High-performance 110 kVp hard x-ray detector based on all-crystalline-surface passivated perovskite single crystals

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InfoMat 2024年第8期6卷 97-110页

作者： Juyoung Ko Beomjun park Jangwon Byun Sandeep Pandey Ajin Jo joo-Hong Lee Wonho Lee Jin-Wook Lee Nam-Gyu park man-Jong Lee Department of Chemistry Konkuk UniversitySeoulRepublic of Korea Advanced Crystal Material/Device Research Center Konkuk UniversitySeoulRepublic of Korea Health Science Research Center Korea UniversitySeoulRepublic of Korea Department of Nano Engineering and Department of Nano Science and Technology SKKU Advanced Institute of Nanotechnology(SAINT)Sungkyunkwan UniversitySuwonRepublic of Korea SKKU Institute of Energy Science&Technology(SIEST) Sungkyunkwan UniversitySuwonRepublic of Korea Department of Health and Environmental Science Korea UniversitySeoulRepublic of Korea School of Chemical Engineering Center for Antibonding Regulated CrystalsSungkyunkwan UniversitySuwonRepublic of Korea

Halide perovskite single crystals(SCs)have attracted much attention for their application in high-performance x-ray detectors owing to their desirable properties,including low defect density,high mobility–lifetime product(μτ),and long carrier diffusion ***,suppressing the inherent defects in perovskites and overcoming the ion migration primarily caused by these defects remains a *** study proposes a facile process for dipping Cs0.05FA0.9MA0.05PbI3 SCs synthesized by a solution-based inverse temperature crystallization method into a 2-phenylethylammonium iodide(PEAI)solution to reduce the number of defects,inhibit ion migration,and increase x-ray *** to conventional spin coating,this simple dipping process forms a two-dimensional PEA2PbI4 layer on all SC surfaces without further treatment,effectively passivating all surfaces of the inherently defective SCs and minimizing ion *** a result,the PEAI-treated perovskite SC-based x-ray detector achieves a record x-ray sensitivity of 1.3×10^(5)μC Gyair^(-1) cm^(-2) with a bias voltage of 30 V at realistic clinical dose rates of 1–5 mGy s^(-1)(peak potential of 110 kVp),which is 6 times more sensitive than an untreated SC-based detector and 3 orders of magnitude more sensitive than a commercialα-Se-based ***,the PEAI-treatedperovskite SC-based x-ray detector exhibits a low detection limit(73 nGy s^(-1)),improved x-ray response,and clear x-ray images by a scanning method,highlighting the effectiveness of the PEAI dipping approach for fabricating next-generation x-ray detectors.

关键词： 2D PEA2PbI4 layers clinical dose rates perovskite single crystals phenethylammonium iodide(PEAI) surface passivation x-ray sensitivity

Carbon Dioxide Concentration and Flux in an Urban Residential Area in Seoul,Korea

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Advances in Atmospheric Sciences 2014年第5期31卷 1101-1112页

作者： Moon-Soo park Seung Jin joo Soon-Ung park Weather Information Service Engine Center for Atmospheric Science & Earthquake ResearchSeoul 121-835 Korea Center for Atmospheric and Environmental Modeling Seoul 152-775 Korea

The carbon dioxide （CO2） concentrations and fluxes measured at a height of 17.5 m above the ground by a sonic anemometer and an open-path gas analyzer at an urban residential site in Seoul, Korea from February 2011 to January 2012 were analyzed. The annual mean CO2 concentration was found to be 750 mg m-3, with a maximum monthly mean concentration of 827 mg m-3 in January and a minimum value of 679 mg m-3 in August. Meanwhile, the annual mean CO2 flux was found to be 0.45 mg m-2 s-1, with a maximum monthly mean flux of 0.91 mg m-2 s-1 in January and a minimum value of 0.19 mg m-2 s-1 in June. The hourly mean CO2 concentration was found to show a significant diurnal variation; a maximum at 0700-0900 LST and a minimum at 1400-1600 LST, with a large diurnal range in winter and a small one in summer, mainly caused by diurnal changes in mixing height, CO2 flux, and surface complexity. The hourly mean CO2 flux was also found to show a significant diurnal variation, but it showed two maxima at 0700-0900 LST and 2100-2400 LST, and two minima at 1100-1500 LST and 0300-0500 LST, mainly caused by a diurnal pattern in CO2 emissions and sinks from road traffic, domestic heating and cooking by liquefied natural gas use, and the different horizontal distribution of CO2 sources and sinks near the site. Differential advection with respect to wind direction was also found to be a cause of diurnal variations in both the CO2 concentration and flux.

关键词： CO2 concentration CO2 flux liquefied natural gas (LNG) Seoul urban residential area

Effect of hafnium and molybdenum addition on inclusion characteristics in Co-based dual-phase high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2024年第7期31卷 1639-1650页

作者： Yong Wang Wei Wang joo Hyun park Wangzhong Mu Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education&Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081China Department of Materials Science and Engineering KTH Royal Institute of TechnologySE-10044StockholmSweden Department of Chemical Engineering Northeast Electric Power UniversityJilin 132012China Department of Materials Science and Chemical Engineering Hanyang UniversityAnsan 15588Korea Engineering Materials Division of Materials ScienceDepartment of Engineering Science and MathematicsLuleå University of Technology97187 LuleåSweden

Specific grades of high-entropy alloys(HEAs)can provide opportunities for optimizing properties toward high-temperature *** this work,the Co-based HEA with a chemical composition of Co_(47.5)Cr_(30)Fe_(7.5)Mn_(7.5)Ni_(7.5)(at%)was *** refractory metallic elements hafnium(Hf)and molybdenum(Mo)were added in small amounts(1.5at%)because of their well-known positive effects on high-temperature *** characteristics were comprehensively explored by using a two-dimensional cross-sectional method and extracted by using a three-dimensional electrolytic extraction *** results revealed that the addition of Hf can reduce Al_(2)O_(3)inclusions and lead to the formation of more stable Hf-rich inclusions as the main *** addition cannot influence the inclusion type but could influence the inclusion characteristics by affecting the physical parameters of the HEA *** calculated coagulation coefficient and collision rate of Al_(2)O_(3)inclusions were higher than those of HfO_(2)inclusions,but the inclusion amount played a larger role in the agglomeration behavior of HfO_(2)and Al_(2)O_(3)*** impurity level and active elements in HEAs were the crucial factors affecting inclusion formation.

关键词： high-entropy alloy non-metallic inclusion agglomeration thermodynamics alloying