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A Centralized Algorithm for Assigning MDC Video Application in Virtual network

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China Communications 2016年第S1期13卷 158-166页

作者： ZHU Kai WU Chunming ZHOU Boyang CHEN Fei WANG Haoxue next generation network laboratory College of Computer Science and Technology Zhejiang University Henan Electrical Power Research Institute State Grid Corporation of China Information Engineering University

Providing services on demand is a major contributing factor to drive the increasingly development of the software defined network. However, it should supply all the current popular applications before it really attains widespread development. Multiple Description Coding(MDC) video applications, as a popular application in the current network, should be reasonably supported in this novel network virtualization environment. In this paper, we address this issue to assign MDC video application into virtual networks with an efficient centralized algorithm(CAMDV). Since this problem is an NP-hard problem, we design an algorithm that can effectively balance the user satisfaction and network resource cost. Previous work just builds a global multicast tree for each description to connect all the destination nodes by breadth-first search strategy or shortest path tree algorithm. But those methods could not achieve an optimal balance or a high-level user satisfaction. By introducing the hierarchical clustering scheme, our algorithm decomposes the whole mapping procedure into multicast tree construction and multipath description distribution. A serial of simulation experiments show that our centralized algorithm could achieve a better performance in balancing the user satisfaction and average mapping cost in comparison with its rivals.

关键词： multiple description coding video multipath programming hierarchical clustering scheme multicast tree construction network virtualization

Performance Evaluation for SDN Deployment: an Approach Based on Stochastic network Calculus

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China Communications 2016年第S1期13卷 98-106页

作者： LIN Changting WU Chunming HUANG Min WEN Zhenyu ZHENG Qiuhua next generation network laboratory College of Computer Science and Technology Zhejiang University Centre for Intelligent Systems and their Applications University of Edinburgh School of Computer Science and Technology Hangzhou Dianzi University

The Open Flow implementations(SDNs) have been deployed increasingly on varieties of networks in research institutions as well as commercial institutions. To develop an Open Flow implementation, it is required to understand the performance of the network. A few benchmark tools(e.g., Cbench and OFlops) can be used to measure the network performance, while these tools take considerable time to simulate traffic behaviors and generate the required results,therefore extending the development time. In this paper, we present an analytical model, which is based on stochastic network calculus theory, for evaluating the performance of switch to *** previous studies show that stochastic network calculus can provide realistic emulation of real network traffic behaviors. Our model is evaluated by using both simulation tool and realistic *** results show the stochastic network calculus based analysis model can realistically measure the network performance of the end-to-end properties between controller and switch.

关键词： software-defined networking endto-end performance stochastic network calculus

Is Minimizing Flow Completion Time the Optimal Way in Meeting Flow's Deadline in Datacenter networks

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China Communications 2016年第S1期13卷 6-15页

作者： XU Yakun LUO Hongbin REN Fei National Engineering laboratory for next generation Internet Technologies School of Electronic and Information Engineering Beijing Jiaotong University

In modern datacenters, the most common method to solve the network latency problem is to minimize flow completion time during the transmission process. Following the soft real-time nature, the optimization of transport latency is relaxed to meet a flow's deadline in deadline-sensitive services. However, none of existing deadline-sensitive protocols consider deadline as a constraint condition of *** can only simplify the objective of meeting a flow's deadline as a deadline-aware mechanism by assigning a higher priority for tight-deadline constrained flows to finish the transmission as soon as possible, which results in an unsatisfactory effect in the condition of high fan-in degree. It drives us to take a step back and rethink whether minimizing flow completion time is the optimal way in meeting flow's deadline. In this paper, we focus on the design of a soft real-time transport protocol with deadline constraint in datacenters and present a flow-based deadline scheduling scheme for datacenter networks(FBDS).FBDS makes the unilateral deadline-aware flow transmission with priority transform into a compound centralized single-machine deadlinebased flow scheduling decision. In addition, FBDS blocks the flow sets and postpones some flows with extra time until their deadlines to make room for the new arriving flows in order to improve the deadline meeting rate. Our simulation resultson flow completion time and deadline meeting rate reveal the potential of FBDS in terms of a considerable deadline-sensitive transport protocol for deadline-sensitive interactive services.

关键词： datacenter networks deadline preemptive scheduling flow completion time

Energy saving with node sleep and power control mechanisms for wireless sensor networks

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The Journal of China Universities of Posts and Telecommunications 2011年第1期18卷 49-59页

作者： WANG Hwang-cheng National Engineering laboratory for next generation Internet Interconnection Devices School of Electronics and Information EngineeringBeijing Jiaotong University

Energy efficiency sleep scheduling in wireless sensor networks is one of the most crucial technologies. In this paper, we propose a simple and feasible synchronous node sleeping and waking mechanisms for small scale wireless sensor networks. Sensor nodes are divided into forwarding nodes and listening nodes. Beacon frame containing sleep command from the coordinator can be forwarded to listening nodes via forwarding nodes. All the nodes in the network can enter sleep at about the same time. Through such network synchronization mechanisms, we can realize synchronous sleep and wake of the entire network. Furthermore, a new power control scheme based on routing protocol （PCBRP） in the medium access control （MAC） layer is proposed. It operates with the help of routing protocol and calculates optimal transmission power according to the distance between neighbor nodes. A mapping table including optimal transmission power and node address is established during the route building procedure. The transmission power can be obtained by searching the table with the address of next-hop neighbor in subsequent data transmissions. The proposed mechanisms are implemented in sensor nodes and are evaluated in a test-bed. The analysis and evaluation based on the experimental results confirm that the proposed energy-saving mechanisms are feasible and effective.

关键词： wireless sensor network energy-saving mechanism synchronous sleep and wake power control micro sensor routing protocol

Highly sensitive fiber refractive index sensor based on side-core holey structure

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Chinese Physics B 2014年第10期23卷 225-229页

作者：韩雅夏历刘德明 next generation Internet Access National Engineering laboratory (NGIA) School of Optical and Electronic InformationHuazhong University of Science and Technology (HUST)

We propose a side-core holey fiber （SCHF）-based surface plasmon resonance （SPR） sensor to achieve high refractive index （RI） sensitivity. The SCHF structure can facilitate analyte filling and enhance the overlapping area of the core mode and surface plasmon polariton （SPP） mode. The coupling properties of the sensor are analyzed by numerical simulation. The maximum sensitivity of 5000 nm/RIU in an RI range of 1.33-1.44, and the average sensitivity of 9295 nm/RIU in an RI range from 1.44 to 1.54 can be obtained.

关键词： holy fiber surface plasmon resonance refractive index fiber sensor

An ultrathin and continuous Li_4Ti_5O_(12) coated carbon nanofiber interlayer for high rate lithium sulfur battery

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Journal of Energy Chemistry 2019年第4期28卷 19-26页

作者： Decheng An Lu Shen Danni Lei Lehong Wang Heng Ye Baohua Li Feiyu Kang Yan-Bing He Engineering laboratory for the next generation Power and Energy Storage Batteries Graduate School at Shenzhen Tsinghua University laboratory of Advanced Materials School of Materials Science and Engineering Tsinghua University

Severe capacity fading and poor high rate performance of lithium sulfur(Li–S) battery caused by "shuttle effect" and low conductivity of sulfur hampers its further developments and applications. Li_4Ti_5O_(12) (LTO)possesses high lithium ion conductivity, and it is also can be used as an active adsorbent for polysulfide. Herein, fine LTO particle coated carbon nanofibers(CNF) were prepared and a conductive network both for electron and lithium ion was built, which can greatly promote the electrochemical conversion of polysulfide and improve the rate performance of Li–S batteries. Meanwhile, a quantity of adsorption sites is constructed by defects of the surface of LTO-CNF membrane to effectively immobilize polysulfide. The multifunctional LTO-CNF interlayer could impede the shuttle effect and enhance comprehensive electrochemical performance of Li–S batteries, especially high rate performance. With such LTO-CNF interlayer,the Li–S battery presents a specific capacity of 641.9 mAh/g at 5 C rate. After 400 cycles at 1 C, a capacity of 618.0 mAh/g is retained. This work provides a feasible strategy to achieve high performance of Li–S battery for practical utilization.

关键词： Lithium sulfur batteries Li4Ti5O12 (LTO) Interlayer Polysulfide adsorbent Polysulfide conversion

MSPnet: MANAGEABLE SIP P2P MEDIA DISTRIBUTION SYSTEM

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Journal of Electronics(China) 2007年第6期24卷 845-853页

作者： He Jie Huang Yongfeng Li Xing next generation network Lab Dept of Electronic Engineering Tsinghua University Beijing 100084 China

The letter proposes a three-layer manageable media distribution network system architecture called MSPnet, which is based on Session Initiation ProtocolIll and Peer to Peer （SIP P2P） technology. MSPnet performs application-level structured DHT routing and resource location among domains and unstructured ones in domain. Except for media distribution, it can be used to support a variety of P2P applications, including video broadcasting, video on demand, VoIP, etc. MSPnet is composed of three layers, namely, the signal control layer, the management layer, and the media transportation layer. The MSPnet prototype consists of the SIP server, the management server, the media server, and the node User Agent （UA）. Results from a prototype experiment in a large-scale Internet environment show that MSPnet is feasible, scalable and manageable.

关键词： Session Initiation Protocol (SIP) Peer to Peer (P2P) SIP server Management server User Agent (UA)

Interface compatibility between sulfide solid electrolytes and Ni-rich oxide cathode materials:Factors,modification,perspectives

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Journal of Energy Chemistry 2025年第2期101卷 233-262页

作者： Tianwen Yang Haijuan Pei Haijian Lv Shijie Lu Qi Liu Daobin Mu Beijing Key laboratory of Environmental Science and Engineering School of Materials Science an Engineering Beijing Institute of Technology State Key laboratory of Space Power-Sources Technology Shanghai Institute of Space Power-Sources

All-solid-state batteries(ASSBs) assembled with sulfide solid electrolytes(SSEs) and nickel(Ni)-rich oxide cathode materials are expected to achieve high energy density and safety,representing potential candidates for the next-generation energy storage ***,interfacial issues between SSEs and Nirich oxide cathode materials,attributed to space charge layer,interfacial side reactions,and mechanical contact failure,significantly restrict the performances of *** interface degradation is closely related to the components of the composite cathode and the process of electrode *** on the influencing factors of interface compatibility between SSEs and Ni-rich oxide cathode,this article systematically discusses how cathode active materials(CAMs),electrolytes,conductive additives,binders,and electrode fabrication impact the interface *** addition,the strategies for the compatibility modification are ***,the challenges and prospects of intensive research on the degradation and modification of the SSE/Ni-rich cathode material interface are *** review is intended to inspire the development of high-energy-density and high-safety all-solid-state batteries.

关键词： All–solid–state batteries Influencing factors Interface compatibility Ni–rich oxide cathode Sulfide solid electrolyte

Extracting the time delay signature of coupled optical chaotic systems by mutual statistical analysis

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Frontiers of Optoelectronics 2017年第4期10卷 378-387页

作者： Xinhua ZHU Mengfan CHENG Lei DENG Xingxing JIANG. Deming LIU next generation Internet Access National Engineering laboratory (NGIA) School of Optical and Electronic Information Huazhong University of Science and Technology Wuhan 430074 China

The time delay （TD） signature is a critical parameter in optical chaos-based applications. The feasi- bility of extracting the TD has been a crucial issue that significantly influences the performance of these applica- tions. In this paper, statistical analyses have been conducted to extract the TD signatures from different types of coupled optical chaos systems. More specifically, a mutually coupled semiconductor laser chaotic system, an intensity-coupled electro-optic chaotic system, and a phase-coupled electro-optic chaotic system are studied in detail. These systems are proposed to resist the attack strategies against the TD signature. They are proved to be effective under statistical analyzes, such as the self- correlation fimction （SF） and mutual information （MI）. However, only a single output has been considered for the attack process in the existing research. We demonstrated that the TD signature can still be extracted by analyzing the mutual statistical relationship between the different output signals which are generated simultaneously by the coupled system. Furthermore, we find that the extraction strategy is effective for a wide parameter range in these schemes.

关键词： optical chaotic system chaos electro-opticnonlinear system time delay (TD) concealment