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Research achievements on the new generation Internet architecture and protocols

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Science China(Information Sciences) 2013年第11期56卷 133-157页

作者： LIU Ying WU JianPing ZHANG Zhou XU Ke Tsinghua national Laboratory for Information Science and Technology (TNList) Institute for network Sciences and Cyberspace Tsinghua University Department of Computer Science and Technology Tsinghua University

Despite the great success achieved by the Internet,it has been facing increasingly severe technical challenges that include address exhaustion,low-level network security and trustworthiness,weak quality-ofservice control capability,limited bandwidth,and poor support toward *** this paper we summarize the principal challenges facing the current Internet,introduce the research status of the future Internet,analyze the principal design goals of the new generation Internet evaluation methods and models of the present Internet architecture,introduce the research achievements made under the new generation Internet architecture in detail,and propose our next-step research priorities and perspectives in the face of an increasing number of innovative Internet applications.

关键词： Internet technical challenges new generation Internet architecture evolvable architecture

A Survey of Testing for 5G:Solutions,Opportunities,and Challenges

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China Communications 2019年第1期16卷 69-85页

作者： Ping Zhang Xiaoli Yang Jianqiao Chen Yuzhen Huang State Key Laboratory of network and Switching Technology Beijing University of Posts and Telecommunications Artificial Intelligence Research Center National Innovation Institute of Defense Technology

With the development of wireless communication technology,the fifth generation mobile communications system(5 G) emerges at a historic moment and devotes itself to open the curtain of the information ***,in order to satisfy the requirement of different applications,various advanced 5 G technologies have been developed in full ***,before applying these 5 G related technologies in practical systems,effective testing methods are needed to evaluate these technologies in a real,comprehensive,rapid and flexible ***,the testing methods are faced with new challenges along with the continuous development of the new 5 G *** this paper,we present a survey of 5 G testing,including solutions and *** particular,two cases are considered,i.e.,channel modelling and overthe-air(OTA) testing of antenna ***,a non-stationary channel model is proposed to characterize and test massive multiple-input multiple-output(MIMO) *** addition,we propose two probe subset selection algorithms for three-dimensional(3 D) OTA testing,which minimizes the number of probe antennas while ensuring the accuracy of the target channel ***,future research directions and challenges on 5 G testing are given.

关键词： 5G testing channel modelling over-the-air testing

A Novel Neighborhood-Weighted Sampling Method for Imbalanced Datasets

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Chinese Journal of Electronics 2022年第5期31卷 969-979页

作者： GUANG Mingjian YAN Chungang LIU Guanjun WANG Junli JIANG Changjun Key Laboratory of Embedded System and Service Computing Tongji University Ministry of Education national (Province-Ministry Joint) Collaborative Innovation Center for Financial network Security Tongji University

The weighted sampling methods based on k-nearest neighbors have been demonstrated to be effective in solving the class imbalance problem. However,they usually ignore the positional relationship between a sample and the heterogeneous samples in its neighborhood when calculating sample weight. This paper proposes a novel neighborhood-weighted based sampling method named NWBBagging to improve the Bagging algorithm’s performance on imbalanced datasets. It considers the positional relationship between the center sample and the heterogeneous samples in its neighborhood when identifying critical samples. And a parameter reduction method is proposed and combined into the ensemble learning framework, which reduces the parameters and increases the classifier’s diversity. We compare NWBBagging with some state-of-the-art ensemble learning algorithms on 34 imbalanced datasets, and the result shows that NWBBagging achieves better performance.

关键词： parameter reduction method neighborhood-weighted sampling method pattern classification class imbalance problem NWBBagging k-nearest neighbors sampling methods imbalanced datasets nearest neighbour methods ensemble learning algorithm Bagging algorithm

Filtering Chinese Image Spam Using Pseudo-OCR

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Chinese Journal of Electronics 2015年第1期24卷 134-139页

作者： XU Bin LI Ruiguang LIU Yashu YAN Hanbing LI Siyuan ZHANG Honggang Beijing University of Posts and Telecommunication national Computer network Emergency Response Technical Team Coordination Center of China Beijing University of Civil Engineering and Architecture Beijing Jiaotong University

For image spam filtering, the Optical character recognition(OCR) based methods often achieve a better performance due to the more complex structure of recognizing corresponding text. However, applying traditional OCR techniques usually introduced shortcomings like the expensive computational cost, vulnerability to image noises and artificial interferences, especially for Chinese image spam filtering. So, by optimizing recognition procedure of traditional OCR, we propose the idea of pseudo-OCR more suitable for Chinese image spam filtering. During which discriminating the potential image spam character features from ham ones is sufficient, instead of recognizing them. What’s more, a novel Chinese key-point based character feature specific for pseudo-OCR is also devised and extracted using a carefully designed algorithm, which outperforms classic corner detection methods in finding such key-points. Experiment results show that our proposed system usually has a better performance than traditional OCR based method while maintaining a low false positive rate.

关键词： Image spam Chinese character recognition Pseudo-OCR.

Locally differentially private high-dimensional data synthesis

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Science China(Information Sciences) 2023年第1期66卷 25-42页

作者： Xue CHEN Cheng WANG Qing YANG Teng HU Changjun JIANG Key Laboratory of Embedded System and Service Computing (Tongji University) Ministry of Education national (Province-Ministry Joint) Collaborative Innovation Center for Financial network Security Tongji University

In local differential privacy(LDP), a challenging problem is the ability to generate highdimensional data while efficiently capturing the correlation between attributes in a dataset. Existing solutions for low-dimensional data synthesis, which partition the privacy budget among all attributes, cease to be effective in high-dimensional scenarios due to the large-scale noise and communication cost caused by the high dimension. In fact, the high-dimensional characteristics not only bring challenges but also make it possible to apply some technologies to break this bottleneck. This paper presents Sam Priv Syn for high-dimensional data synthesis under LDP, which is composed of a marginal sampling module and a data generation *** marginal sampling module is used to sample from the original data to obtain two-way marginals. The sampling process is based on mutual information, which is updated iteratively to retain, as much as possible,the correlation between attributes. The data generation module is used to reconstruct the synthetic dataset from the sampled two-way marginals. Furthermore, this study conducted comparison experiments on the real-world datasets to demonstrate the effectiveness and efficiency of the proposed method, with results proving that Sam PrivSyn can not only protect privacy but also retain the correlation information between the attributes.

关键词： local differential privacy high-dimensional data synthesis sampling data privacy privacy-preserving protocols

An efficient multipath routing schema in multi-homing scenario based on protocol-oblivious forwarding

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Frontiers of Computer Science 2020年第4期14卷 95-105页

作者： Pufang MA Jiali YOU Jinlin WANG national network New Media Engineering Research Center Institute of AcousticsChinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China

With the advent of 5G,multi-homing will be an increasingly common scenario,which is expected to increase transmission rates,improve transmission reliability,and reduce costs for ***,the current routing methods are unable to fully utilize the resources of networks to achieve high-performance data transmission for multi-homed *** the current routing mechanism,there is only one destination address in the packet forwarded to the multi-homed ***,the packet is difficult to adjust its path on the fly according to the status of the network to achieve better *** this paper,we present an efficient routing schema in multi-homing scenario based on protocol-oblivious forwarding(POF).In the proposed schema,the packet forwarded to the multi-homed host carries multiple destination addresses to obtain the ability of switching the transmission path;meanwhile,the router dynamically adjusts the path of the packet through the perception of the network *** results show that our schema could utilize the alternative paths properly and significantly improve the transmission efficiency.

关键词： multi-homing routing software-defined networking protocol-oblivious forwarding

Hierarchical caches in content-centric networks： modeling and analysis

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Frontiers of Computer Science 2015年第6期9卷 846-859页

作者： Zixiao JIA Jiwei HUANG Chuang LIN Department of Computer Science and Technology Tsinghua University Beijing 100084 China national Computer network Emergency Response Technical Team/Coordination Center of China Beijing 100029 China

Content-centric network （CCN） is a new Inter- net architecture in which content is treated as the primitive of communication. In CCN, routers are equipped with con- tent stores at the content level, which act as caches for fre- quently requested content. Based on this design, the Internet is available to provide content distribution services without any application-layer support. In addition, as caches are inte- grated into routers, the overall performance of CCN will be deeply affected by the caching efficiency. In this paper, our aim is to gain some insights on how caches should be designed to maintain a high performance in a cost-efficient way. We try to model the two-layer cache hi- erarchy composed of CCN touters using a two-dimensional discrete-time Markov chain, and develop an efficient algo- rithm to calculate the hit ratios of these caches. Simulations validate the accuracy of our modeling method, and convey some meaningful information which can help us better un- derstand the caching mechanism of CCN.

关键词： CCN cache model analysis

Structure overset grid method and its applications to simulation of multi-body separation

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Science China(Physics,Mechanics & Astronomy) 2015年第9期58卷 68-75页

作者： ZHANG HaiRui FAN JingJing YUAN Wu ZHANG WeiHua College of Aerospace Science and Engineering National University of Defense Technology China Academy of Lanch Vehicle Technology Supercomputing Center Computer Network Information Center Chinese Academy of Sciences

This paper proposes an automatic structure overset grid method, which utilizes the hole-surface optimization with one-step searching, wall-surface grid oversetting, and dynamic overset grid approaches to achieve the high adaptability of overset grids for complex multi-body aircrafts. Specifically, based on the automatic structure overset grids, the method first solves the coupling of Navier-Stokes(N-S) unsteady flow equation and 6DOF motion equation, and establishes the multi-body collision model. Then, the numerical simulation of unsteady flow for complex aircrafts' multi-body separation, the simulation of multi-body separating trajectory and the separation safety analysis are accomplished. Thus, the method can properly handle practical engineering problems including the wing/drop tank separation, aircraft/mount separation, and cluster bomb projection. Experiments show that our numerical results match well with experimental results, which demonstrates the effectiveness of our methods in solving the multi-body separation problem for aircrafts with complex shapes.

关键词： dynamic overset grids multi-body separations CFD

Computing Power network:The Architecture of Convergence of Computing and networking towards 6G Requirement

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China Communications 2021年第2期18卷 175-185页

作者： Xiongyan Tang Chang Cao Youxiang Wang Shuai Zhang Ying Liu Mingxuan Li Tao He Future network Research Department China Unicom Network Technology Research InstituteBeijing 100048China

In 6G era,service forms in which computing power acts as the core will be ubiquitous in the *** the same time,the collaboration among edge computing,cloud computing and network is needed to support edge computing service with strong demand for computing power,so as to realize the optimization of resource *** on this,the article discusses the research background,key techniques and main application scenarios of computing power *** the demonstration,it can be concluded that the technical solution of computing power network can effectively meet the multi-level deployment and flexible scheduling needs of the future 6G business for computing,storage and network,and adapt to the integration needs of computing power and network in various scenarios,such as user oriented,government enterprise oriented,computing power open and so on.

关键词： 6G edge computing cloud computing convergence of cloud and network computing power network