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Efficient Virtual Network Embedding Algorithm Based on Restrictive Selection and Optimization Theory Approach

China Communications 2017年第10期14卷 39-60页

作者： Haotong Cao zhicheng qu Yishi Xue Longxiang Yang College of Communication and Information Engineering Nanjing University of Posts and Telecommunications Nanjing China Wolfson School of Mechanical Electrical and Manufacturing Engineering Loughborough University Leicestershire UK Key Laboratory of Broadband Wireless Communication and Sensor Network Technique Ministry of Education Nanjing University of Postsand Telecommunications Nanjing China Wireless Communication Key Laboratory of Jiangsu Province Nanjing University of Posts and Telecommunications Nanjing China

Network virtualization(NV) is widely considered as a key component of the future network and promises to allow multiple virtual networks(VNs) with different protocols to coexist on a shared substrate network(SN). One main challenge in NV is virtual network embedding(VNE). VNE is a NPhard problem. Previous VNE algorithms in the literature are mostly heuristic, while the remaining algorithms are exact. Heuristic algorithms aim to find a feasible embedding of each VN, not optimal or sub-optimal, in polynomial time. Though presenting the optimal or sub-optimal embedding per VN, exact algorithms are too time-consuming in smallscaled networks, not to mention moderately sized networks. To make a trade-off between the heuristic and the exact, this paper presents an effective algorithm, labeled as VNE-RSOT(Restrictive Selection and Optimization Theory), to solve the VNE problem. The VNERSOT can embed virtual nodes and links per VN simultaneously. The restrictive selection contributes to selecting candidate substrate nodes and paths and largely cuts down on the number of integer variables, used in the following optimization theory approach. The VNE-RSOT fights to minimize substrate resource consumption and accommodates more VNs. To highlight the efficiency of VNERSOT, a simulation against typical and stateof-art heuristic algorithms and a pure exact algorithm is made. Numerical results reveal that virtual network request(VNR) acceptance ratio of VNE-RSOT is, at least, 10% higher than the best-behaved heuristic. Other metrics, such as the execution time, are also plotted to emphasize and highlight the efficiency of VNE-RSOT.

关键词： network virtualization virtual network embedding NP-hard heuristic exact restrictive selection optimization theory

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Heuristic Solutions of Virtual Network Embedding： A Survey

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China Communications 2018年第3期15卷 186-219页

作者： Haotong Cao Han Hu zhicheng qu Longxiang Yang College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China College of lntemet of Things Nanjing University of Posts and Telecommunications Nanjing 210003 China Jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and Telecommunications Nanjing 210003 China

Network virtualization(NV) is considered as an enabling tool to remove the gradual ossification of current Internet. In the network virtualization environment, a set of heterogeneous virtual networks(VNs), isolated from each other, share the underlying resources of one or multiple substrate networks(SNs) according to the resource allocation strategy. This kind of resource allocation strategy is commonly known as so called Virtual Network Embedding(VNE) algorithm in network virtualization. Owing to the common sense that VNE problem is NP-hard in nature, most of VNE algorithms proposed in the literature are heuristic. This paper surveys and analyzes a number of representative heuristic solutions in the literature. Apart from the analysis of representative heuristic solutions, a taxonomy of the heuristic solutions is also presented in the form of table. Future research directions of VNE, especially for the heuristics, are emphasized and highlighted at the end of this survey.

关键词： network virtualization virtual net-work embedding NP-hard heuristic solution

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Stochastic Dynamic Modeling of Rain Attenuation: A Survey

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China Communications 2018年第3期15卷 220-235页

作者： zhicheng qu Gengxin Zhang Haotong Cao Jidong Xie College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Satellite & Mobile communication Section Nanjing University of Posts and Telecommunications National Local Joint Engineering Research Center for communication and network technology Nanjing University of Posts and Telecommunications Key Laboratory of Broadband Wireless Communication and Sensor Network Technique of Ministry of Education Nanjing University of Posts and Telecommunications

Satellite communication systems(SCS) operating on frequency bands above 10 GHz are sensitive to atmosphere physical phenomena, especially rain attenuation. To evaluate impairments in satellite performance, stochastic dynamic modeling(SDM) is considered as an effective way to predict real-time satellite channel fading caused by rain. This article carries out a survey of SDM using stochastic differential equations(SDEs) currently in the literature. Special attention is given to the different input characteristics of each model to satisfy specific local conditions. Future research directions in SDM are also suggested in this paper.

关键词： stochastic dynamic modeling rainattenuation time-series synthesizer satellitecommunication satellite link stochastic dif-ferential equations

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基于InVEST-PLUS模型的黄河流域内蒙古段生态系统碳储量评价及预测

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干旱区研究 2024年第7期41卷 1217-1227页

作者：李冰洁范志韬曲芷程姚顺予宿夏姝刘东伟王立新内蒙古大学生态与环境学院内蒙古呼和浩特010021 蒙古高原生态学与资源利用教育部重点实验室内蒙古呼和浩特010021

陆地生态系统碳储量对减缓全球气候变暖有重要意义,评估黄河流域内蒙古段土地利用变化对碳储量变化的影响,可以为“双碳”目标的实现提供助力。本研究运用InVEST模型对黄河流域内蒙古段过去20 a的碳储量进行评估,运用PLUS模型预测了2040... 详细信息

陆地生态系统碳储量对减缓全球气候变暖有重要意义,评估黄河流域内蒙古段土地利用变化对碳储量变化的影响,可以为“双碳”目标的实现提供助力。本研究运用InVEST模型对黄河流域内蒙古段过去20 a的碳储量进行评估,运用PLUS模型预测了2040年3种不同发展情景下的土地利用格局,并耦合InVEST-PLUS对黄河流域内蒙古段未来20 a的碳储量进行估算,探讨土地利用变化和碳储量之间的响应关系。结果表明:2000—2020年黄河流域内蒙古段草地是主要土地利用类型和最重要的碳库。草地面积增加是黄河流域内蒙古段碳储量上升的主要原因,碳储量累计上升4.08×10^(7)t。在生态保护情景下,最有利于2040年黄河流域内蒙古段碳储量的增加,可使碳储量累计增加4.50×10^(7)t。年均降水是解释度最高的单因子影响因素,随着社会经济的发展,社会经济因子对碳储量时空分异特征的解释度增加。双因子交互影响的解释度普遍远高于单因子对于碳储量时空分异特征的解释度。本研究以期为区域用地规划提供建议,为我国更好的实现碳中和目标提供服务。

关键词：碳储量土地利用变化 InVEST模型 PLUS模型黄河流域内蒙古段

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A Novel Roll Compensation Method for Two-Axis Transportable Satellite Antennas

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China Communications 2018年第3期15卷 137-148页

作者： Laiding Zhao Jidong Xie Xiaodong Bai zhicheng qu College of Telecommunications and Information Engineering Nanjing University of Posts and Telecommunications Nanjing 210003 China Satellite Communication and Navigation Collaborative Innovation Center Nanjing 210003 China

Two-axis transportable satellite antennas(TATSAs) have been widely adopted owing to its simple structure and low cost. However, by searching in a wide range, it will take a very long searching time. Under extreme conditions, it will even fail to work. In this paper, we propose a novel roll compensation(RC) method for the low-cost TATSAs to achieve faster tracking even if when the antenna has no azimuth sensor. By analyzing the influence of roll axis on the system performance, details of the compensation method are derived. Simulation and measurement results indicate that the proposed RC method can effectively reduce the initial searching time for satellite communication. In addition, tracking along with the ellipse path with the RC method provides the highest tracking efficiency.

关键词： two-axis transportable satelliteantenna (TATSA) satellite tracking roll com-pensation (RC) searching time.

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Photonic devices based on thin-film lithium niobate on insulator

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Journal of Semiconductors 2021年第4期42卷 43-52页

作者： Shuai Yuan Changran Hu An Pan Yuedi Ding Xuanhao Wang zhicheng qu Junjie Wei Yuheng Liu Cheng Zeng† Jinsong Xia Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

Lithium niobate on insulator(LNOI)is rising as one of the most promising platforms for integrated photonics due to the high-index-contrast and excellent material properties of lithium niobate,such as wideband transparency from visible to mid-infrared,large electro-optic,piezoelectric,and second-order harmonic *** fast-developing micro-and nanostructuring techniques on LNOI have enabled various structure,devices,systems,and *** this contribution,we review the latest developments in this platform,including ultra-high speed electro-optic modulators,optical frequency combs,opto-electro-mechanical system on chip,second-harmonic generation in periodically poled LN waveguides,and efficient edge coupling for LNOI.

关键词： thin-film lithium niobate modulator PPLN edge coupler

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Space-Terrestrial Integrated Architecture for Internet of Things

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ZTE Communications 2020年第4期18卷 3-9页

作者： ZHANG Gengxin DING Xiaojin qu zhicheng Telecommunication and Networks National Engineering Research Center Nanjing University of Posts and TelecommunicationsNanjing 210003China

To realize the ultimate vision of Internet of Things(IoT),only depending on terrestrial network is far from *** a supplement and extension of terrestrial network,satellite network can offer powerful support to realize the depth and breadth of the ***,existing satellite networks are usually designed for particular ***,traditional satellite networks and terrestrial networks are developed and operated separately,consequently they cannot meet the need of network flexibility required by *** this paper,a space-terrestrial architecture is conceived for constructing a spaceterrestrial based IoT(ST-IoT) ***,a reliable identification procedure,an integrated access and communication procedure,as well as a clustering cooperative transmission strategy are also presented.

关键词： Internet of Things system architecture space-terrestrial integrated network

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基于代谢组学研究针刺腰痛点治疗泌尿系结石肾绞痛的作用机制

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北京中医药 2024年第7期43卷 729-737页

作者：曲志成屠建锋胡晶彭伟裴晓璐王爽郭飒姚卫海刘存志曹迎首都医科大学附属北京中医医院急诊和危重症救治中心北京100010 北京中医药大学针灸推拿学院北京100029 北京市中医药研究所北京100010 首都医科大学附属北京中医医院护理部北京100010

目的观察针刺腰痛点治疗泌尿系结石急性肾绞痛的有效性,并基于代谢组学探讨其作用机制。方法本研究为探索性随机对照试验,将20例泌尿系结石肾绞痛患者随机分为试验组与对照组,每组各10例。试验组采用针刺双侧腰痛点,对照组采用非穴点浅... 详细信息

目的观察针刺腰痛点治疗泌尿系结石急性肾绞痛的有效性,并基于代谢组学探讨其作用机制。方法本研究为探索性随机对照试验,将20例泌尿系结石肾绞痛患者随机分为试验组与对照组,每组各10例。试验组采用针刺双侧腰痛点,对照组采用非穴点浅刺治疗。观察比较2组患者针刺操作后10 min的疼痛缓解率;治疗前后采用色谱-质谱联用技术的非靶向代谢组学方法对2组血清进行检测。对检测出的代谢物根据P值、差异倍数变化以及计算变量投影重要度值进行差异筛选,利用Spearman相关系数,与临床指标相结合,进行差异代谢物的进一步筛选,基于KEGG数据库进行功能通路富集分析。结果针刺操作后10 min,试验组较对照组获得更高的疼痛缓解率80.0%(95%CI 38.4%~94.3%,P<0.01)。代谢组学:试验组治疗前后对比,筛选出差异代谢物199个;对照组治疗前后对比,筛选出差异代谢物54个;试验组对比对照组,筛选出差异代谢物325个。对试验组治疗前后代谢物变化与NRS疼痛评分Spearman等级相关分析发现,鸟苷等4个差异代谢物与NRS疼痛评分呈负相关,阿尔巴黄酮等9个差异代谢物与NRS疼痛评分呈正相关;试验组较对照组代谢物变化与NRS疼痛评分Spearman等级相关分析发现,3-醛基水杨酸等3个差异代谢物与NRS疼痛评分呈负相关,皮质醇等8个差异代谢物与NRS疼痛评分呈正相关。试验组对比对照组,富集到通路9条,其中与疼痛调节相关的通路为色氨酸代谢途径和不饱和脂肪酸的生物合成代谢途径。结论针刺腰痛点可快速缓解泌尿系结石肾绞痛,调节鸟苷、鸟嘌呤、皮质醇等代谢产物表达,影响色氨酸代谢途径与不饱和脂肪酸的生物合成代谢途径,可能是针刺治疗肾绞痛的潜在作用机制。

关键词：腰痛点肾绞痛针刺镇痛代谢组学作用机制

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Time-Periodic Solutions to quasilinear Hyperbolic Systems on General Networks

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 41-72页

作者： Peng qu School of Mathematical Sciences Fudan UniversityShanghai 200433China

For quasilinear hyperbolic systems on general networks with time-periodic boundary-interface conditions with a dissipative structure,the existence and stability of the time-periodic classical solutions are discussed.

关键词： Time-periodic solution quasilinear hyperbolic system General net-work Classical solution Asymptotic stability

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Pathways toward a pollution-free planet and challenges

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Frontiers of Environmental Science & Engineering 2024年第6期18卷 3-8页

作者： Jiuhui qu Jiaping Chen School of Environment Tsinghua UniversityBeijing 100084China College of Chemistry and Environmental Engineering Shenzhen UniversityShenzhen 518060China

The mission of“Establishment of Zero-Pollution Earth”defined by United Nations Environment Programme aims at creation of a clean,safe and prosperous home for all human *** is of rational choice from each individual to protect our environment and demonstrates our great ambition to achieve our *** key message given in this article is that,zero pollution does not mean no discharge of pollutants and instead it can be achievable through optimizing and controlling a sound balance between pollutants discharge and capacities of decontamination through treatment and natural environmental accumulation,which can be termed as“Principle of Equilibrium”between pollution and *** on this principle,we propose and illustrate several key factors and synergistic pathways toward a pollution-free planet:quantitative determination on purification and wastewater;source control through green measures;minimization of negative side-effects;precise management through digitalized systems;and keeping sound balance between pollutants and natural *** should be noted that we would face a series of difficulties and challenges in moving forward to“Zero-Pollution Earth”.We should further develop theories,principles and tools to achieve the balance between quantity of pollutants and decontamination *** should work together to break through the bottleneck limited by“Principle of equilibrium”to establish new environmental remediation systems leading to“Zero-Pollution Earth”.

关键词： Wastewater treatment Resources Recovery Greenhouse gases Energy Pollution-free

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