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A parameter-free upwind scheme for all speeds' simulations

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Science China(Technological Sciences) 2015年第3期58卷 434-442页

作者： QU Feng YAN Chao SUN Di YUAN Wu National Laboratory for CFD Beihang University Supercomputting center Computer Network Information Center Chinese Academy of Sciences

With the rapid development of the computational fluid dynamics(CFD),a parameter-free upwind scheme capable of simulating all speeds accurately and efficiently is in high *** achieve this goal,we present a new upwind scheme called AUSMPWM in this *** scheme computes the numerical mass flux as the AUSMPW+and computes the interfacial sound speed in a different ***,it computes the pressure flux by limiting the dissipation if the Mach number is less than *** of numerical experiments show that AUSMPWM can satisfy the following attractive properties independent of any tuning coefficient:(1)Robustness against the shock anomaly and high discontinuity’s resolution;(2)high accuracy on hypersonic heating prediction and capability to give smooth reproductions of heating profiles;(3)low dissipation at low speeds;and(4)strong grid,reconstruction scheme,and Mach number independence in low speeds’*** properties suggest that AUSMPWM is promising to be widely used to accurately and efficiently simulate flows of all speeds.

关键词： shock anomaly AUSMPW+ ausmpwm all speeds computational fluid dynamics

APPOW:An Advanced Routing Protocol Based on Parameters Optimization in the Weighted Mobile Social network

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China Communications 2016年第S1期13卷 107-115页

作者： HUO Yan QI Jinghao LI Zhen JING Tao Shuhua Wireless network and information Perception center School of Electronics and Information Engineering Beijing Jiaotong University

Due to the increasing number of wireless mobile devices,the possibility of mobile communications without infrastructure becomes a *** Decentralized Mobile Social network(DMSN) is a paradigm where nodes can move freely and organize themselves *** in these environments is difficult for the reason of the rapid changes of the social relationship graph's ***,the social ties among nodes change ***,an efficient data forwarding mechanism should be considered over the temporal weighted relationship *** this paper,an Advanced routing Protocol based on Parameters Optimization in the Weighted mobile social network(APPOW) is proposed to improve the delivery success ratio and reduce the cost of exchanging *** combines the normalized relative weights of three local social metrics,i.e.,LinkRank,similarity and contact strength,to select the next relay *** weights of the three metrics are derived by pair-wise learning *** result shows that APPOW outperforms the state-ofthe-art SimBet Routing in delivering message and significantly reduces the average ***,the delivery performance of APPOW is close to Epidemic Routing but without message duplications.

关键词： link rank similarity contact strength routing protocol mobile social network

Novel quantum watermarking algorithm based on improved least significant qubit modification for quantum audio

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Chinese Physics B 2018年第1期27卷 267-277页

作者：瞿治国何煌兴李涛 Jiangsu Engineering center of network Monitoring Nanjing University of Information Science and Technology School of Electronic & information Engineering Nanjing University of Information Science and Technology

As one of essential multimedia in quantum networks, the copyright protection of quantum audio has gradually be- come an important issue in the domain of quantum information hiding in the decades. In this paper, an improved quantum watermarking algorithm based on quantum audio by using least significant qubit （LSQb） modification is proposed. Com- pared with the previous achievements, it can effectively improve the robustness and security of watermark for copyright protection of quantum audio. In the new algorithm, the least significant bites and the peripheral least significant bits of the amplitudes are modified in terms of their logical consistency and correlation to enhance watermark robustness of resisting various illegal attacks. Furthermore, the new algorithm can avoid the weak robustness defect of many previous algorithms that directly embedded the watermark into the least significant bits. In order to implement the new algorithm, some spe- cific quantum circuits are designed to obtain better applicability and scalability for embedding and extracting watermark. Finally, the simulation results including the values of audio waveforms and signal to noise ratios （SNR） prove that the new algorithm has good transparency, robustness, and security.

关键词： quantum audio watermarking least significant qubit logical consistency and correlation quantumcircuits

Three-dimensional Numerical Simulation of Viscoelastic Phase Separation under Shear: the Roles of Bulk and Shear Relaxation Moduli

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Chinese Journal of Polymer Science 2015年第11期33卷 1562-1573页

作者： Jing-yi Chen Zhong Jin 杨科大 School of Materials Science and Engineering Beihang University Supercomputing center Computer Network Information Center Chinese Academy of Sciences

The morphological, dynamic and rheological characteristics in the viscoelastic phase separation（VPS） of sheared polymer solutions are investigated by three-dimensional（3D） numerical simulations of viscoelastic model. The simulations are accelerated by graphic process unit（GPU） to break through the limitation of computation power. Firstly, the morphological and dynamic characteristics of VPS under shear are presented by comparing with those in classic phase separation（CPS）. The results show that the phase inversion and phase shrink take place in VPS under shear. Then, the roles of bulk and shear relaxation moduli in VPS are investigated in details. The bulk relaxation modulus slows down the phase separation process under shear, but not affects the dynamic path of VPS. The dynamic path can be divided into three stages： freezing stage, growth stage and stable stage. The second overshoot phenomenon in the shear stress is observed, and explained by the breakdown and reform of string structures. The shear modulus affects morphology evolution in the late stage of VPS under shear.

关键词： Viscoelastic model Phase separation Polymer solution Shear

Short Video Recommendation Algorithm Incorporating Temporal Contextual information and User Context

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Computer Modeling in Engineering & Sciences 2023年第4期135卷 239-258页

作者： Weihua Liu Haoyang Wan Boyuan Yan network Security and information management center Jining UniversityJining272000China School of Computer Science Qufu Normal UniversityRizhao276800China

With the popularity of 5G and the rapid development of mobile terminals,an endless stream of short video software *** short-form mobile video in fragmented time has become the mainstream of user’s ***,designing an efficient short video recommendation method has become important for major network platforms to attract users and satisfy their ***,the explosive growth of data leads to the low efficiency of the algorithm,which fails to distill users’points of interest on one hand *** the other hand,integrating user preferences and the content of items urgently intensify the requirements for platform *** this paper,we propose a collaborative filtering algorithm,integrating time context information and user context,which pours attention into expanding and discovering user *** the first place,we introduce the temporal context information into the typical collaborative filtering algorithm,and leverage the popularity penalty function to weight the similarity between recommended short videos and the historical short *** remains one more *** also introduce the user situation into the traditional collaborative filtering recommendation algorithm,considering the context information of users in the generation recommendation stage,and weight the recommended short-formvideos of *** last,a diverse approach is used to generate a Top-K recommendation list for *** through a case study,we illustrate the accuracy and diversity of the proposed method.

关键词： Recommendation algorithm user contexts short video temporal contextual information

Multilevel Pattern Mining Architecture for Automatic network Monitoring in Heterogeneous Wireless Communication networks

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China Communications 2016年第7期13卷 108-116页

作者： Zhiguo Qu John Keeney Sebastian Robitzsch Faisal Zaman Xiaojun Wang Jiangsu Engineering center of network Monitoring Nanjing University of Information Science and TechnologyNanjing 210044China School of Electronic Engineering Dublin City UniversityDublinIreland network management Lab AthloneIreland

The rapid development of network technology and its evolution toward heterogeneous networks has increased the demand to support automatic monitoring and the management of heterogeneous wireless communication *** paper presents a multilevel pattern mining architecture to support automatic network management by discovering interesting patterns from telecom network monitoring *** architecture leverages and combines existing frequent itemset discovery over data streams,association rule deduction,frequent sequential pattern mining,and frequent temporal pattern mining techniques while also making use of distributed processing platforms to achieve high-volume throughput.

关键词： automatic network monitoring sequential pattern mining episode discovery module

Optimal migration path of Ag in HfO_2: A first-principles study

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Chinese Physics B 2015年第7期24卷 193-199页

作者：代月花陈真金波李宁李晓风 Institute of Electronic and information Engineering Anhui University Internet network information center Hefei Institutes of Physical ScienceChinese Academy of Sciences

First-principles calculations are used to investigate the migration path of Ag in the HfO2-based resistive random access memory（Re RAM）. The formation energy calculation suggests that there are two different sites（site 1 and site 3） for the incorporation of Ag atoms into the HfO2 unit cell. Thermodynamic analysis shows that the motion of Ag atom in the HfO2 supercell appears to be anisotropic, which is due to the fact that the Ag atom at site 3 moves along the [1ˉ11] orientation,but the Ag atom at site 1 moves along the [001] orientation. The migration barriers of the Ag atoms hopping between neighboring unit cells are calculated along five different orientations. Difficulty in producing motion of the Ag atom varies with the migration barrier： this motion is minimized along [1ˉ11] orientation. Furthermore, The optimal circulation path for Ag migration within the HfO2 supercells is obtained, and is found to be approximately along the [1ˉ11] ***, it is proposed that the positive voltage should be applied along this orientation, the conduction filament may form more easily, which could improve the response time and reduce the power consumption in Re RAM applications.

关键词： HfO2 resistive random access memory Ag migration migration orientation

Finding Main Causes of Elevator Accidents via Multi-Dimensional Association Rule in Edge Computing Environment

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China Communications 2017年第11期14卷 39-47页

作者： Hongman Wang Mengqi Zeng Zijie Xiong Fangchun Yang Institute of network Technology Engineering Research Center of Information Network Ministry of EducationBeijing University of Posts and Telecommunications Beijing China

In order to discover the main causes of elevator group accidents in edge computing environment, a multi-dimensional data model of elevator accident data is established by using data cube technology, proposing and implementing a method by combining classical Apriori algorithm with the model, digging out frequent items of elevator accident data to explore the main reasons for the occurrence of elevator accidents. In addition, a collaborative edge model of elevator accidents is set to achieve data sharing, making it possible to check the detail of each cause to confirm the causes of elevator accidents. Lastly the association rules are applied to find the law of elevator Accidents.

关键词： elevator group accidents apriori multi-dimensional association rules data cube edge computing

A Correlation Visual Analytics System for Air Quality

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Chinese Journal of Electronics 2018年第5期27卷 920-926页

作者： DU Yi Abish Malik ZHOU Lianke ZHOU Yuanchun Department of Big Data Technology and Application Development Computer Network Information CenterChinese Academy of Sciences

A visual analytics system is proposed to reveal the lead/lag correlation when air pollution is detected. In this system, an Overview + Detail approach is utilized for analyzing the correlation of air quality under both the spatial and temporal dimensions and different spatial-temporal scales. An annular container is proposed to preserve the context spatial information while the zoom level of the map changes. Based on the annular container, several analysis techniques such as STL decomposition view and correlation algorithm are integrated.

关键词： Spatial-temporal visualization Time series visualization Correlation analysis Air pollution