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Topology-assisted deterministic packet marking for IP traceback

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The Journal of China Universities of Posts and Telecommunications 2010年第2期17卷 116-121页

作者： wang xiao-jing wang xiao-yin Laboratory of Computer Network Defense Technology Beijing Institute of Technology Beijing 100081 China Xi'an Politics Institute Xi'an 710068 China

A novel deterministic packet marking （DPM） for IP traceback against denial of service （DOS） and distributed denial of service （DDoS） attacks is presented, which features good scalability and high accuracy. In this scheme, an ingress router pre-calculates a Hash of its IP address and splits the Hash into several fragments. When marking a packet, the router randomly selects a fragment to mark into the packet. In the traceback stage the victim identifies the marked router with the help of the map of its upstream routers. Based on the map, the victim can identify a candidate ingress router after receiving only several marked packets. The scheme overcomes defects in previous deterministic packet marking schemes, where too much packets are required to recover a router and high false positive rate occurs in case of large-scale DDoS. Theoretical analysis, the pseudo code and experimental results are provided. The scheme is proved to be accurate and efficient and can handle large-scale DDoS attacks.

关键词： network security DDoS 1P traceback deterministic packet marking (DPM)

A Trust Region Affine Scaling Method for Bound Constrained Optimization

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Acta Mathematica Sinica,English Series 2013年第1期29卷 159-182页

作者： xiao wang School of Mathematical Sciences University of Chinese Academy of Sciences

We study a new trust region affine scaling method for general bound constrained optimiza- tion problems. At each iteration, we compute two trial steps. We compute one along some direction obtained by solving an appropriate quadratic model in an ellipsoidal region. This region is defined by an affine scaling technique. It depends on both the distances of current iterate to boundaries and the trust region radius. For convergence and avoiding iterations trapped around nonstationary points, an auxiliary step is defined along some newly defined approximate projected gradient. By choosing the one which achieves more reduction of the quadratic model from the two above steps as the trial step to generate next iterate, we prove that the iterates generated by the new algorithm are not bounded away from stationary points. And also assuming that the second-order sufficient condition holds at some nondegenerate stationary point, we prove the Q-linear convergence of the objective function values. Preliminary numerical experience for problems with bound constraints from the CUTEr collection is also reported.

关键词： Bound constrained optimization affine scaling trust region approximate projected gradient

L^p Solutions of Backward Stochastic Volterra Integral Equations

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Acta Mathematica Sinica,English Series 2012年第9期28卷 1875-1882页

作者： Tian xiao wang School of Mathematics Shandong University

This paper is devoted to the unique solvability of backward stochastic Volterra integral equations （BSVIEs, for short）, in terms of both M-solution and the adapted solutions. We prove the existence and uniqueness of M-solutions of BSVIEs in Lp （1 〈 p 〈 2）, which extends the existing results on M-solutions. The unique solvability of adapted solutions of BSVIEs in Lp （p 〉 1） is also considered, which also generalizes the results in the existing literature.

关键词： Backward stochastic Volterra integral equations M-solutions Lp solutions adapted solutions

An improved multiple model GM-PHD filter for maneuvering target tracking

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Chinese Journal of Aeronautics 2013年第1期26卷 179-185页

作者： wang xiao Han Chongzhao The Flight Automatic Control Research Institute of AVIC School of Electronic and Information Engineering Xi'an Jiaotong University

In this paper, an improved implementation of multiple model Gaussian mixture probability hypothesis density （MM-GM-PHD） filter is proposed. For maneuvering target tracking, based on joint distribution, the existing MM-GM-PHD filter is relatively complex. To simplify the filter, model conditioned distribution and model probability are used in the improved MM-GM-PHD filter. In the algorithm, every Gaussian components describing existing, birth and spawned targets are estimated by multiple model method. The final results of the Gaussian components are the fusion of multiple model estimations. The algorithm does not need to compute the joint PHD distribution and has a simpler computation procedure. Compared with single model GM-PHD, the algorithm gives more accurate estimation on the number and state of the targets. Compared with the existing MM-GM-PHD algorithm, it saves computation time by more than 30%. Moreover, it also outperforms the interacting multiple model joint probabilistic data association （IMMJPDA） filter in a relatively dense clutter environment.

关键词： Estimation Gaussian mixture Maneuvering target racking Multiple model Probability hypothesis density

Ultrafiltration with in-line coagulation for the removal of natural humic acid and membrane fouling mechanism

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Journal of Environmental Sciences 2006年第5期18卷 880-884页

作者： wang Jin wang xiao-chang Department of Municipal and Environmental Engineering Beijing Jiaotong University Beijing 100044 China School of Environmental and Municipal Engineering Xi＇an University of Architecture and Technology Xi＇an 710055 China

Experimental and theoretical analysis were made on the natural humic acid removal and the membrane fouling of ultrafiltration （UF） with in-line coagulation. The results showed dissolved organic carbon （DOC） and UV254 removals by the UF with in-line coagulation at pH 7 were increased from 28% to 53% and 40% to 78% in comparison with direct UF treatment respectively. At the same time, the analysis of high performance liquid chromatography showed that UF with coagulation had significant improvement of removal of humic acid with molecular weights less than 6000 Da in particular. Compared to direct UF, the in-line coagulation UF also kept more constant permeate flux and very slight increase oftransmembrane pressure during a filtration circle. Two typical membrane fouling models were used by inducing two coefficients Kc and Kp corresponding to cake filtration model and pore narrowing model respectively. It was found that membrane fouling by pore-narrowing effect was effectively alleviated and that by cake-filtration was much decreased by in-line coagulation. Under the condition of coagulation prior to ultrafiltration at pH 7, the cake layer formed on the membrane surface became thicker, but the membrane filtration resistance was lower than that at pH 5 with the extension of operation time.

关键词： natural humic acid ultrafiltration (UF) in-line coagulation high performance liquid chromatography (HPLC) membrane fouling

Phase constitution of the noble metal thin-film complex solid solution system Ag-Ir-Pd-Pt-Ru in dependence of elemental compositions and annealing temperatures

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Nano Research 2022年第6期15卷 4827-4836页

作者： Bin xiao xiao wang Alan Savan Alfred Ludwig Materials Discovery and Interfaces Institute for MaterialsRuhr University Bochum44780 BochumGermany Zentrum für Grenzflächendominierte Höchstleistungswerkstoffe(ZGH) Ruhr University Bochum44780 BochumGermany

Multiple-principal element alloys hold great promise for multifunctional material discovery(e.g.,for novel electrocatalysts based on complex solid solutions)in a virtually unlimited compositional ***,the phase constitution of the noble metal system Ag-Ir-Pd-Pt-Ru was investigated over a large compositional range in the quinary composition space and for different annealing temperatures from 600 to 900°C using thin-film materials ***-dependent X-ray diffraction mapping of the asdeposited thin-film materials library indicates different phases being present across the composition space(face-centered cubic(fcc),hexagonal close packed(hcp)and mixed fcc+hcp),which are strongly dependent on the Ru *** general,low Ru contents promote the fcc phase,whereas high Ru contents favor the formation of an hcp solid-solution ***,a temperature-induced phase transformation study was carried out for a selected measurement area of fcc-Ag_(5)Ir_(8)Pd_(56)Pt_(8)Ru_(23).With increasing temperature,the initial fcc phase transforms to an intermediate C14-type Laves phase at 360°C,and then to hcp when the temperature reaches 510°*** formation and disappearance of the hexagonal Laves phase,which covers a wide temperature range,plays a crucial role of bridging the fcc to hcp phase *** obtained composition,phase and temperature data are transformed into phase maps which could be used to guide theoretical studies and lay a basis for tuning the functional properties of these materials.

关键词： noble metal high-entropy alloys phase transformation combinatorial synthesis and high-throughput characterization

Stress and thickness calculation of a bolted flat cover with double metal sealing rings

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Nuclear Science and Techniques 2018年第8期29卷 210-217页

作者： xiao-Yan wang Shi-Feng Zhu xiao wang xiao-Chun Zhang Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

The design of a bolted flat cover is extremely important for the structural integrity of pressure *** present design codes provide the thickness calculation equations for a bolted flat cover with single metal ***,the rules for a bolted flat cover with double metal sealing rings are not developed to *** the study,a new thickness calculation equation for the bolted flat cover with double metal sealing rings is ***,the theoretical stress solution for bolted flat cover with the double metal sealing rings is obtained,based on the theory of simply supported circular plate and then verified using the results from finite element *** results indicate that the influence of double metal sealing ring on the stress of the flat cover is more serious compared to single metal ***,a more accurate and reasonable equation is proposed to calculate the thickness of bolted flat cover with double metal sealing rings based on the derived theoretical equations of maximum ***,the influence of linear load and the spacing between rings on the thickness are ***,a few suggestions are provided to design low-pressure or atmosphere pressure *** study provides a theoretical foundation to develop design codes of pressure vessels in nuclear reactors.

关键词：厚度计算扁平金属封面戒指应力和计算方程压力解

Creep damage characterization of UNS N10003 alloy based on a numerical simulation using the Norton creep law and Kachanov–Rabotnov creep damage model

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Nuclear Science and Techniques 2019年第4期30卷 114-122页

作者： xiao-Yan wang xiao wang xiao-Chun Zhang Shi-Feng Zhu Shanghai Institute of Applied Physics Chinese Academy of Sciences University of Chinese Academy of Sciences

The calculation of inelastic creep damage is important for the structural integrity evaluation of the elevated temperature structure in a thorium molten salt reactor(TMSR). However, a creep damage theory model and numerical simulation method have not been proposed for the key materials(UNS N10003 alloy) in the TMSR. In this study, creep damage characterization of UNS N10003 alloy is investigated using the Norton creep law and Kachanov–Rabotnov(K–R) creep damage model. First, the creep experimental data of the UNS N10003 alloy at 650 °C were adopted to fit the material constants of the two models. Then, the creep damage behavior of the UNS N10003 alloy was analyzed and discussed under uniaxial and multi-axial stress states. The results indicated that the K–R creep damage model is more suitable for the UNS N10003 alloy than the Norton model. Finally, the numerical simulation method was developed by a user-defined UMAT subroutine and subsequently verified through a finite element analysis(FEA). The FEA results were in agreement with the theoretical solutions. This study provides an effective method for the inelastic creep damage analysis of the elevated temperature structure in the TMSR.

关键词： Thorium molten salt reactor UNS N10003 alloy Creep damage Inelastic analysis Elevated temperature structure

Computational Experiments for Complex Social Systems:Integrated Design of Experiment System

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1175-1189页

作者： xiao Xue Xiangning Yu Deyu Zhou xiao wang Chongke Bi Shufang wang Fei-Yue wang College of Intelligence and Computing Tianjin UniversityTianjin 300350China School of Software Shandong UniversityJinan 250101China School of Artificial Intelligence Anhui UniversityHefei 230601China School of Geographic and Environmental Sciences Tianjin Normal UniversityTianjin 300387China Institute of Automation Chinese Academy of Sciences Beijing 100190China

Powered by advanced information industry and intelligent technology,more and more complex systems are exhibiting characteristics of the cyber-physical-social systems(CPSS).And human factors have become crucial in the operations of complex social *** mechanical analysis and social simulations alone are powerless for analyzing complex social *** this backdrop,computational experiments have emerged as a new method for quantitative analysis of complex social systems by combining social simulation(e.g.,ABM),complexity science,and domain ***,in the process of applying computational experiments,the construction of experiment system not only considers a large number of artificial society models,but also involves a large amount of data and *** a result,how to integrate various data,model and knowledge to achieve a running experiment system has become a key *** paper proposes an integrated design framework of computational experiment system,which is composed of four parts:generation of digital subject,generation of digital object,design of operation engine,and construction of experiment ***,this paper outlines a typical case study of coal mine emergency management to verify the validity of the proposed framework.

关键词： artificial system operations