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基于自适应Sketch的高速网络流大小测量机制

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中国科学：信息科学 2024年第7期54卷 1677-1691页

作者：卜霄菲黄河孙玉娥王兆杰吴晓灿沈阳师范大学软件学院沈阳110034 苏州大学计算机科学与技术学院苏州215006 苏州大学轨道交通学院苏州215131

高速网络流大小的测量面临着高速存储资源极度稀缺的挑战,难以满足海量流式数据的实时存储需求.目前的研究大多采用存储资源共享技术,以便将设计的估计器置于稀缺的高速片上缓存中.然而,这种方法引入了大量难以消除的噪声,导致中小规模... 详细信息

高速网络流大小的测量面临着高速存储资源极度稀缺的挑战,难以满足海量流式数据的实时存储需求.目前的研究大多采用存储资源共享技术,以便将设计的估计器置于稀缺的高速片上缓存中.然而,这种方法引入了大量难以消除的噪声,导致中小规模流的估算精度不高.为了解决这一问题,本文提出一种能根据流大小自适应调整所占用存储空间的自适应Sketch技术,并在此基础上设计出一个高精度、低存储开销的每流大小估计器.自适应Sketch技术利用可逆计数器高效滤除海量噪声小流,并进一步采用采样概率逐层递减的采样计数器实现对不同规模流的自适应采样计数,从而控制大流对资源的过多占用,实现了低开销、高精度的每流大小测量.基于真实网络数据集CAIDA 2019的仿真实验表明,所提出的自适应Sketch流大小估计器的平均相对误差较现有机制降低了接近1个数量级.

关键词：高速网络流大小测量 Sketch 噪声小流过滤可逆计数器

Privacy-Preserving Strategyproof Auction Mechanisms for Resource Allocation

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Tsinghua Science and Technology 2017年第2期22卷 119-134页

作者： yu-e sun He Huang Xiang-Yang Li Yang Du Miaomiao Tian Hongli Xu Mingjun Xiao School of Urban Rail Transportation Soochow University School of Computer Science and Technology Soochow University School of Computer Science and Technology University of Science and Technology of China Suzhou Institute for Advanced Study University of Science and Technology of China School of Computer Science and Technology Anhui University

In recent years, auction theory has been extensively studied and many state-of-the-art solutions have been proposed aiming at allocating scarce resources. However, most of these studies assume that the auctioneer is always trustworthy in the sealed-bid auctions, which is not always true in a more realistic scenario. Besides the privacy-preserving issue, the performance guarantee of social efficiency maximization is also crucial for auction mechanism design. In this paper, we study the auction mechanisms that consider the above two aspects. We discuss two multi-unit auction models： the identical multiple-items auction and the distinct multiple-items *** the problem of determining a multi-unit auction mechanism that can maximize its social efficiency is NPhard, we design a series of nearly optimal multi-unit auction mechanisms for the proposed models. We prove that the proposed auction mechanisms are strategyproof. Moreover, we also prove that the privacy of bid value from each bidder can be preserved in the auction mechanisms. To the best of our knowledge, this is the first work on the strategyproof multi-unit auction mechanisms that simultaneously consider privacy preservation and social efficiency maximization. The extensive simulations show that the proposed mechanisms have low computation and communication overheads.

关键词： approximation mechanism multi-unit auction privacy preserving social efficiency strategyproof

Persistent Variations in the east Asian Trough from March to April and the Possible Mechanism

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Advances in Atmospheric Sciences 2024年第4期41卷 737-753,I0002-I0004页

作者： Shui yu Jianqi sun Nansen-Zhu International Research Center Institute of Atmospheric PhysicsChinese Academy of SciencesBeijing 100029China College of earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China

The east Asian trough(eAT)profoundly influences the east Asian spring *** this study,the relationship of the eATs among the three spring months is *** analysis shows that the variation in March eAT is closely related to that of April *** empirical orthogonal function(eeOF)analysis also confirms the co-variation of the March and April *** positive/negative eeOF1 features the persistent strengthened/weakened eAT from March to *** investigation indicates that the variations in eeOF1 are related to a dipole sea surface temperature(SST)pattern over the North Atlantic and the SST anomaly over the tropical Indian *** dipole SST pattern over the North Atlantic,with one center east of Newfoundland Island and another east of Bermuda,could trigger a Rossby wave train to influence the eAT in March−*** SST anomaly over the tropical Indian Ocean can change the Walker circulation and influence the atmospheric circulation over the tropical western Pacific,subsequently impacting the southern part of the eAT in March−*** the SST factors,the Northeast Asian snow cover could change the regional thermal conditions and lead to persistent eAT anomalies from March to *** three impact factors are generally independent of each other,jointly explaining large variations in the eAT ***,the signals of the three factors could be traced back to February,consequently providing a potential prediction source for the eAT variation in March and April.

关键词： spring east Asian trough sea surface temperature snow cover

Cooperative game penetration guidance for multiple hypersonic vehicles under safety critical framework

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Chinese Journal of Aeronautics 2024年第1期37卷 247-255页

作者： Jieqing CHeN Ruisheng sun yu LU School of energy and Power engineering Nanjing University of Science and TechnologyNanjing 210094China

The rapid development of the anti-missile weapon technology brings new challenges to the cooperative penetration strategy solution and the guidance law design for Hypersonic Vehicles(HVs).This paper studies the coordinated game penetration guidance problem for multiple hypersonic vehicles faced with space threat areas.A scheme for seeking cooperative game penetration guidance strategy under safety critical control framework is *** this scheme,a multiHV cooperative game model is proposed in a minimum optimization form which can simplify the solving process and accelerate the computing ***,a second-order control barrier function is developed to transform the implicit nonlinear constraints of the proposed model into linear *** order to obtain better performance of guidance strategy,a composite guidance law under the safety critical control framework is presented to allocate guidance strategies appropriately in the whole *** is shown that the proposed scheme can guarantee successful penetration while avoiding threat ***,a comparative simulation with a two-on-three game is conducted to verify the effectiveness of the proposed method.

关键词： Hypersonic vehicles Safety critical control Penetration game Space constraints Cooperative guidance

The Use of Multislice Spiral CT to Predict the Resectability of Central Lung Cancer： Correlation with Pathologic and Surgical Findings

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Chinese Journal of Clinical Oncology 2005年第4期2卷 726-730页

作者： Yang Liu yu＇e sun Naikang Zhou Qiming Xu Department of Thoracic Surgery General Hospital of the PLA Beijing 100853 China.

OBJeCTIVe To assess the accuracy of multi-slice spiral CT （MSCT） with imaging reconstruction in judging central pulmonary vascular involvement from central lung cancer, and to explore its ability to predict the resectability of lung cancer. MeTHODS MSCTs were conducted on 48 patients who were diagnosed preoperatively with central lung cancer. Images of pulmonary arteries and veins that might affect Iobectomy or pneumonectomy were reconstructed by means of imaging processing techniques. Then the relationship of the tumor to the vessels was assessed prospectively on both axial CT images and axial CT images plus reconstructed images（CT-RI） in comparison to subsequent pathologic and surgical findings. ReSULTS MSCTs were obtained on all 48 patients whom 42 underwent thoracotomy, Iobectomy or pneumonectomy. Compared with the axial CT images, CT-RI was more accurate in judging the relationship of the central pulmonary vessels to the tumor based on subsequent pathologic 78 vessels studied and surgical findings （186 vessels studied）（0.01 〈P〈0.05）. The sensitivity and positive predictive value of unresectability of the vessels were all remarkably higher with CT-RI （P〈0.01）. CONCLUSION MSCT with imaging reconstruction can improve the recognition of neoplastic invasion of central pulmonary vessels. It can be used to predict preoperatively the resectability of central lung cancer and to plan surgery.

关键词： lung neoplasm thoracotomy tomography X-ray computed pathology

Direct numerical simulation of shock wave/boundary layer interaction controlled by steady microjet in a compression ramp

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Chinese Journal of Aeronautics 2024年第10期37卷 83-102页

作者： Ruoye XIAO Dong sun Jian yu School of Aeronautic Science and engineering Beihang UniversityBeijing 100191China State Key Laboratory of Aerodynamics Mianyang 621000China

Shock wave/boundary layer interaction in a 24°turning angle of the compression ramp at Mach number 2.9 controlled by steady microjet is investigated using direct numerical *** different jet spacings which are termed as sparse,moderate and dense are considered,and the induced vortex system and shock structures are compared.A moderate jet spacing configuration is found to generate counter-rotating vortex pairs that transport high-momentum fluid towards the vicinity of wall and strengthen the boundary layer to resist separation,reducing the separation *** dense jet spacing configuration creates a larger momentum deficit region,reducing the friction downstream of the *** of pressure and pressure gradient reveals that dense jet spacing configuration reduces the intensity of separation *** impact of varying jet spacings on the turbulent kinetic energy transport mechanism is also investigated by decomposing the budget terms in the transport ***,the spectral characteristics of the separation region are studied using power spectral density and dynamic mode decomposition methods,revealing that moderate jet spacing configuration suppresses low-frequency fluctuations in the separation region.

关键词： Shock wave/boundary layer interaction Compression ramp Steady microjet Different jet spacings Direct numerical simulation

A Note on Gradient estimates for elliptic equations with Discontinuous Coefficients

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 1-10页

作者： yu PeNG Xiandong sun Huichun ZHANG Department of Mathematics Sun Yat-Sen UniversityGuangzhou 510275China.

The authors will use a method in metric geometry to show an L^(P)-estimate for gradient of the weak solutions to elliptic equations with discontinuous coefficients,even the BMO semi-norms of the coefficients are not *... 详细信息

关键词： L^(p)-estimate elliptic equation Discontinuous coefficients

Application of system identification in a practical active noise control system

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Control Theory and Technology 2024年第2期22卷 282-291页

作者： yu yuan Zhaoyang sun Hongwei Zhang School of Mechanical engineering Xihua UniversityChengdu610039SichuanChina School of electrical engineering Southwest Jiaotong UniversityChengdu611756SichuanChina School of Mechanical engineering and Automation Harbin Institute of TechnologyShenzhen518055GuangdongChina

Noise pollution has become increasingly severe around the world due to fast urbanization. How to soundproof windows from outside noise is of significant interest for both academia and industry. This paper reports an experimental implementation of normalized minmax active noise control (ANC) algorithm on an open window system, where identifying the model of acoustic sound paths plays a central role. By doing this, traffic noise is attenuated by the ANC system, leading to a relatively quiet indoor environment, while the natural lighting and ventilation functions of a window are remained. Our experiments show that an average of 19 dB(A) noise reduction is achieved.

关键词： Active noise control Multi-input-multi-output system Normalized minimax algorithm System identification

An improved high-fidelity adaptive model for integrated inlet-engine-nozzle based on mechanismdata fusion

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Chinese Journal of Aeronautics 2024年第8期37卷 190-207页

作者： Chen WANG Ziyang yu Xian DU Ximing sun School of Control Science and engineering Dalian University of TechnologyDalian 116024China Key Laboratory of Intelligent Control and Optimization for Industrial equipment Ministry of EducationDalian University of TechnologyDalian 116024China

Nowadays,there has been an increasing focus on integrated flight propulsion control and the inlet-exhaust design for the aero-propulsion *** component-level models are inadequate due to installed performance deviations and mismatches between the real engine and the model,failing to meet the accuracy requirements of supersonic *** paper establishes a quasi-one-dimensional model for the inlet-exhaust system and conducts experimental ***,a mechanism-data fusion adaptive modeling scheme using an extreme Learning Machine based on the Salp Swarm Algorithm(SSA-eLM)is *** study reveals the inlet model’s efficacy in reflecting installed performance,flow matching,and mitigating pressure distortion,while the nozzle model accurately predicts flow coefficients and thrust coefficients,and identifies various operational *** model’s output closely aligns with typical experimental *** combining offline optimization and online adaptive correction,the mechanismdata fusion adaptive model substantially reduces output errors during regular flights and varying levels of degradation,and effectively handles gradual degradation within a single flight ***,the mechanism-data fusion adaptive model holistically addresses total pressure errors within the inlet-exhaust system and normal shock location *** approach significantly curbs performance deviations in supersonic *** example,at Ma=2.0,the system error impressively drops from 34.17%to merely 6.54%,while errors for other flight conditions consistently stay below the 2.95%*** findings underscore the clear superiority of the proposed method.

关键词： Aero-propulsion system Integrated inlet-enginenozzle Component-level model On-board adaptive model Mechanism-data fusion extreme learning machine