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Machine-Learning Based Packet Switching Method for Providing Stable High-Quality Video Streaming in Multi-Stream Transmission

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Computers, Materials & Continua 2024年第3期78卷 4153-4176页

作者： Yumin jo jongho Paik Major in Software Fusion Department of ComputerSeoulWomen’s UniversitySeoul01797South Korea Department of Software Convergence Seoul Women’s UniversitySeoul01797South Korea

Broadcasting gateway equipment generally uses a method of simply switching to a spare input stream when a failure occurs in a main input ***,when the transmission environment is unstable,problems such as reduction in the lifespan of equipment due to frequent switching and interruption,delay,and stoppage of services may ***,applying a machine learning(ML)method,which is possible to automatically judge and classify network-related service anomaly,and switch multi-input signals without dropping or changing signals by predicting or quickly determining the time of error occurrence for smooth stream switching when there are problems such as transmission errors,is *** this paper,we propose an intelligent packet switching method based on the ML method of classification,which is one of the supervised learning methods,that presents the risk level of abnormal multi-stream occurring in broadcasting gateway equipment based on ***,we subdivide the risk levels obtained from classification techniques into probabilities and then derive vectorized representative values for each attribute value of the collected input data and continuously update *** obtained reference vector value is used for switching judgment through the cosine similarity value between input data obtained when a dangerous situation *** the broadcasting gateway equipment to which the proposed method is applied,it is possible to perform more stable and smarter switching than before by solving problems of reliability and broadcasting accidents of the equipment and can maintain stable video streaming as well.

关键词： Broadcasting and communication convergence multi-stream packet switching advanced television systems committee standard 3.0(ATSC 3.0) data pre-processing machine learning cosine similarity

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Structural metamaterials with negative mechanical/thermomechanical indices: A review

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Progress in Natural Science:Materials International 2021年第6期31卷 801-808页

作者： jo?o O.Cardoso jo?o Paulo Borges Alexandre Velhinho CENIMAT/i3N Departamento de Ciência dos Materiais Faculdade de Ciências e Tecnologia Universidade Nova de Lisboa

Structural metamaterials presenting negative values of one or more mechanical and thermomechanical indices–namely the Poisson's ratio, the linear compressibility, and the coefficient of thermal expansion – are the promising candidates to the applications in many fields, ranging from precision mechanics to biomedical devices or energy absorption. Although scattered mentions may be found in the literature since the late eighties of 20th century, the systematic research efforts concerning these materials became effective much later. The present work is to review the main scientific contributions to the topic in the last five years. This paper first deals with those metamaterials showing a single negative index, and then proceeds to analyze the much less frequent instances of coupled negative indices, with emphasis on the so-called anepectic case, which exhibits an unusual thermomechanical response.

关键词： Mechanical and thermomechanical metamaterials Auxetic Anepectic Negative Poisson's ratio Negative thermal expansion Negative linear compressibility

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A Note on the Universal Factorization Property of Groups

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Algebra Colloquium 2021年第4期28卷 635-644页

作者： Injo Hur Jang Hyun jo Department of Mathematics Education Chonnam National University Gwangju 61186Korea Department of Mathematics Sogang UniversitySeoul 04107Korea

We give criteria when a full subcategory D of the category of groups has C-universal factorization property(C-UFP)or C-strong universal factorization property(C-SUFP)for a certain category of groups *** a byproduct,we give affirmative answers to three unsettled questions in[***,***,Universal factorization property of certain polycyclic groups,*** *** 204(2006)555-567].

关键词： hereditary productive universal factorization property

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One-dimensional titania nanotubes annealed at various temperatures for the photocatalytic degradation of low concentration gaseous pollutants

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Particuology 2015年第2期13卷 86-92页

作者： Ho-Hwan Chun Wan-Kuen jo Department of Naval Architecture and Ocean Engineering Pusan National University Department of Environmental Engineering Kyungpook National University

In this study, one-dimensional titania nanotubes （TNTs） were synthesized using a combined process of chemical and hydrothermal treatments, and their activities for the photocatalytic reactions of selected gaseous pollutants at sub-ppm levels were determined. Additionally, the properties of the TNTs were examined using selected spectroscopic methods. The annealed TNTs showed higher photocatalytic activities for the four target compounds than did the unannealed TNTs. For all the target compounds except benzene, the effect of the annealing temperature on the degradation efficiency was difficult to determine because all degradation efficiencies were very high. However, for benzene, which decomposed with a low efficiency, the degradation activities of the TNTs increased as the treatment temperature was increased from 250 to 300 ℃, while they decreased slightly when the temperature was increased from 300 to 400 ℃. These findings confirm the presence of an optimal annealing temperature for the synthesis of TNTs. Moreover, the average degradation extents for benzene, toluene, ethylbenzene, and o-xylene decreased from 92%, 96%, 99%, and 98% to 77%, 86%, 92%, and 94%, respectively, as the airstream flow rate increased within the range of 1-4L/min. The average degradation extents decreased from 12%, 75%, 87%, and 88% to 3%, 29%, 46%, and 51%, respectively, as the input concentration increased from 0.4 to 1.9 ppm. Overall, these findings suggest that one-dimensional TNTs can be effectively utilized for the degradation of gaseous pollutants under optimal operational conditions.

关键词： vGaseous pollutant Annealing temperature Degradation efficiency Airstream flow rate

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GPU-Driven Scalable Parser for OBJ Models

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journal of Computer Science & Technology 2018年第2期33卷 417-428页

作者： Sunghun jo Yuna Jeong Sungkil Lee Department of Software Sungkyunkwan University Suwon 16419 Korea

This paper presents a scalable parser framework using graphics processing units （GPUs） for massive text-based files. Specifically, our solution is designed to efficiently parse Wavefront OBJ models texts of which specify 3D geometries and their topology. Our work bases its scalability and efficiency on chunk-based processing. The entire parsing problem is subdivided into subproblems the chunk of which can be processed independently and merged seamlessly. The within-chunk processing is made highly parallel, leveraged by GPUs. Our approach thereby overcomes the bottlenecks of the existing OBJ parsers. Experiments performed to assess the performance of our system showed that our solutions significantly outperform the existing CPU-based solutions and GPU-based solutions as well.

关键词： 3D model Wavefront OBJ parser GPU

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Photocatalytic decomposition of mobile-source related pollutants using a continuous-flow reactor

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journal of Environmental Sciences 2010年第3期22卷 460-466页

作者： Wan-Kuen jo Seung-Ho Shin Department of Environmental Engineering Kyungpook National University

This study evaluated the application of a continuous-flow photocatalytic reactor for the control of two mobile-derived pollutants, methyl-tertiary butyl ether （MTBE） and naphthalene, present at in-vehicle levels. Variables tested for this study included the hydraulic diameter （HD）, stream flow rate （SFR）, relative humidity （RH）, and feeding type （FT）. The fixed parameters included contaminant concentration, ultraviolet light source, and the weight of TiO2. In all experimental conditions the adsorption process reached equilibrium within 30 to 180 min for the target compounds, and the outlet concentrations of the photocatalytic oxidation （PCO） reactor while operating reached a steady state within 60 to 180 min. The degradation of the target compounds was dependent on RH, HD, FT, or SFR. The PCO system exhibited high degradation （up to nearly 100% for certain conditions） and mineralization efficiencies of target compounds, suggesting that this system can effiectively be employed to improve indoor air quality. Moreover, it was confirmed that trichloroethylene at urban-ambient level also could enhance the degradation efficiency of naphthalene when applying the PCO technology inside vehicles.

关键词： in-vehicle level methyl-tertiary butyl ether naphthalene trichloroethylene

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Distributed Coordinator Election Scheme for QoS Support and Seamless Connectivity in WPANs

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journal of Computer Science & Technology 2009年第6期24卷 1138-1148页

作者： Soon-Gyu Jeong Sang-jo Yoo Graduate School of Information Technology & Telecommunications Inha University

Wireless personal area networks （WPANs） are formed in a relatively small area, and coordinator that serves as a central control device plays an important role in the operation and organization of a piconet. Typical applications of WPANs include home automation systems, security systems and health monitoring systems. In these types of systems, guaranteeing seamless connectivity is very important, and communications cannot take place when the coordinator malfunctions. Thus, in the case of a breakdown, it is necessary to elect a new coordinator as soon as possible. For this reason, a distributed coordinator election scheme （DCES） is proposed that considers not only QoS support but also network connectivity in an effort to avoid possible network partition. Simulation results show that the proposed scheme can elect a new coordinator while maintaining QoS and guaranteeing connectivity for a limited period.

关键词： QoS seamless connectivity leader election piconet coordinator (PNC) wireless personal area network (WPAN)

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Indolo[3,2,1-jk]carbazole-derived planar electron transport materials realizing high efficiency in green phosphorescent organic light-emitting diodes

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Science China Materials 2023年第11期66卷 4437-4444页

作者： Sejeong Um Unhyeok jo Jun Yeob Lee School of Chemical Engineering Sungkyunkwan University 2066Seobu-roJangan-guSuwonGyeonggi16419Republic of Korea SKKU Advanced Institute of Nano Technology Sungkyunkwan University 2066Seobu-roJangan-guSuwonGyeonggi16419Republic of Korea SKKU Institute of Energy Science and Technology Sungkyunkwan University 2066Seobu-roJangan-guSuwonGyeonggi16419Republic of Korea

Two novel electron transporting materials(ETMs),2-(4,6-diphenyl-1,3,5-triazin-2-yl)indolo[3,2,1-jk]-carbazole(DPTrz-ICz)and 5,11-bis(4,6-diphenyl-1,3,5-triazin-2-yl)-2-phenylindolo[3,2,1-jk]carbazole(2DPTrz-ICz),were developed based on the indolo[3,2,1-jk]carbazole(ICz)core,combined with 2,4-diphenyl-1,3,5-triazine(DPTrz).The introduced ICz core in ETM exhibited enhanced intermolecular charge transport properties owing to its planar and rigid geometry and high triplet energy,demonstrating the potential of designing ***,2DPTrz-ICz,featuring high triplet energy of 2.84 eV,effectively prevented triplet exciton quenching and showed increased electron mobility owing to the activation of intermolecular hopping charge transfer facilitated by stacking *** two materials were utilized as ETMs in green phosphorescent organic light-emitting diodes.2DPTrz-ICz exhibited a superior external quantum efficiency of 21.5%,higher than that of the spirobifluorene-derived ETM.

关键词： electron transport layer indolocarbazole efficiency OLED

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Flexural-wave-generation using a phononic crystal with a piezoelectric defect

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Applied Mathematics and Mechanics(English Edition) 2023年第8期44卷 1241-1262页

作者： S.H.jo D.LEE Department of Mechanical Roboticsand Energy EngineeringDongguk UniversitySeoul 04620Republic of Korea Department of Mechanical Engineering Seoul National UniversitySeoul 08826Republic of Korea

This paper proposes a method to amplify the performance of a flexural-wave-generation system by utilizing the energy-localization characteristics of a phononic crystal(PnC)with a piezoelectric defect and an analytical approach that accelerates the predictions of such wave-generation *** proposed analytical model is based on the Euler-Bernoulli beam *** proposed analytical approach,inspired by the transfer matrix and S-parameter methods,is used to perform band-structure and time-harmonic analyses.A comparison of the results of the proposed approach with those of the finite element method validates the high predictive capability and time efficiency of the proposed model.A case study is explored;the results demonstrate an almost ten-fold amplification of the velocity amplitudes of flexural waves leaving at a defect-band frequency,compared with a system without the ***,design guidelines for piezoelectric-defect-introduced PnCs are provided by analyzing the changes in wave-generation performance that arise depending on the defect location.

关键词： phononic crystal(PnC) defect wave-generation fexural wave analytical model

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Evolution of forest cover in Portugal: A review of the 12th–20th centuries

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journal of Forestry Research 2014年第2期25卷 249-256页

作者： Fernando Reboredo joo Pais Universidade Nova de Lisboa Faculdade de Ciências e TecnologiaCICEGeDepartmento de Ciências da Terra

Portugal＇s forests in the 12th century were dominated by the Fagaceae represented by Quercus and Castanea, and several pine species From the 12th century onwards, forests underwent changes in their management starting with protection and ultimately leading to intense exploitation. The massive naval construction during the maritime expansion （mainly in the 15th-16th centuries） involved felling of approximately 5 million trees mainly Quercus suber, Pinus pinea and other Quercus species. Cumulative fuel-wood consumption of 959 Mm3 during 1300-1854 was attributed to demographic expansion while the deforestation rate during 1636-1854 accounted for a minimum of 72.6% and a maximum of 96% of total forest cover. The volume of timber used in railway sleepers from 1856 onwards might have reached 0.5 Mm3. The last quarter of the 20th century increased the forest cover of Portugal through the World Bank program of Eucalyptus globulus reforestation.

关键词： forest cover change forest exploitation forest economics Portugal.

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