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A Resource-Based Pricing Collaborative Approach for Mitigating DDoS Attack in Mobile Edge Computing

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China Communications 2022年第12期19卷 160-175页

作者： Lu Chen hongbo Tang wei You Yi Bai Information Engineering University Zhengzhou 450002China

Resource-constrainted and located closer to users,edge servers are more vulnerable to Distributed Denial of Service(DDoS)attacks.In order to mitigate the impact of DDoS attacks on benign users,this paper designed a Resource-based Pricing Collaborative approach(RPC)in mobile edge computing.By introducing the influence of resource prices on requester in economics,a collaboration model based on resource pricing was established,and the allocation of user request was regarded as a game strategy to obtain the overall minimum offloading cost of the user in network.The article theoretically proved the existence and rationality of the Nash equilibrium.Finally,simulation results verified the effectiveness and feasibility of the proposed approach in two experimental scenes.Experimental results shows that RPC can effectively improve the network ability to mitigate DDoS attacks,and alleviate the adverse effects of server attacks under delay constraints.

关键词： mobile edge computing DDoS attacks resource-based pricing game theory Nash equilibrium

Potassium ferrate pretreatment promotes short chain fatty acids yield and antibiotics reduction in acidogenic fermentation of sewage sludge

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Journal of Environmental Sciences 2022年第10期34卷 41-52页

作者： Zihao Qiao Suyun Xu Wanqiu Zhang Shuyin Shi wei Zhang hongbo Liu School of Environment and Architecture University of Shanghai for Science and TechnologyShanghai 200093China Centillion Resource Recycling(Wuxi)Co.Ltd. Wuxi 214000China

During the acidogenic fermentation converting waste activated sludge (WAS) into shortchain fatty acids (SCFA), hydrolysis of complex organic polymers is a limiting step and the transformation of harmful substances (such as antibiotics) during acidogenic fermentation is unknown. In this study, potassium ferrate (KFeO) oxidation was used as a pretreatment strategy for WAS acidogenic fermentation to increase the hydrolysis of sludge and destruct the harmful antibiotics. Pretreatment with KFeOcan effectively increase the SCFA production during acidogenic fermentation and change the distribution of SCFA components.With the dosage of 0.2 g/g TS, the maximum SCFA yield was 4823 mg COD/L, which is 28.3times that of the control group;acetic acid accounts for more than 90% of the total SCFA. The higher dosage (0.5 g/g TS) can further increase the proportion of acetic acid, but inhibit the overall performance of SCFA production. Apart from the promotion of hydrolysis and acidogenesis, KFeOpretreatment can also simultaneously oxidizes and degrades part of the antibiotics in the sludge. When the dosage is 0.5 g/g TS, the degradation efficacy of antibiotics is the most significant, and the contents of ofloxacin, azithromycin, and tetracycline in the sludge are reduced by 69%, 42%, and 50%, respectively. In addition, KFeOpretreatment can also promote the release of antibiotics from sludge flocs, which is conducive to the simultaneous degradation of antibiotics in the subsequent biological treatment process.

关键词： Acidogenic fermentation Antibiotics Potassium ferrate Oxidation pretreatment Sewage sludge Volatile fatty acids

Multi-Objective Weather Routing Algorithm for Ships Based on Hybrid Particle Swarm Optimization

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Journal of Ocean University of China 2022年第1期21卷 28-38页

作者： ZHAO wei WANG hongbo GENG Jianning HU Wenmei ZHANG Zhanshuo ZHANG Guangyu State Key Laboratory on Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130000China China State Shipbuilding Corporation(CSSC)Marine Technology Co. Ltd.Beijing 100070China

Maritime transportation has become an important part of the international trade system.To promote its sustainable de-velopment,it is necessary to reduce the fuel consumption of ships,decrease navigation risks,and shorten the navigation time.Ac-cordingly,planning a multi-objective route for ships is an effective way to achieve these goals.In this paper,we propose a multi-ob-jective optimal ship weather routing system framework.Based on this framework,a ship route model,ship fuel consumption model,and navigation risk model are established,and a non-dominated sorting and multi-objective ship weather routing algorithm based on particle swarm optimization is proposed.To fasten the convergence of the algorithm and improve the diversity of route solutions,a mutation operation and an elite selection operation are introduced in the algorithm.Based on the Pareto optimal front and Pareto optimal solution set obtained by the algorithm,a recommended route selection criterion is designed.Finally,two sets of simulated navigation simulation experiments on a container ship are conducted.The experimental results show that the proposed multi-objective optimal weather routing system can be used to plan a ship route with low navigation risk,short navigation time,and low fuel consumption,fulfilling the safety,efficiency,and economic goals.

关键词： weather routing particle swarm optimization route planning multi-objective optimization

Investigation of the influence of intermediate principal stress on the dynamic responses of rocks subjected to true triaxial stress state

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International Journal of Mining Science and Technology 2021年第5期31卷 913-926页

作者： wei You Feng Dai Yi Liu hongbo Du Ruochen Jiang State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu 610065China

Precisely understanding the dynamic mechanical properties and failure modes of rocks subjected to true triaxial stress state(σ1>σ2>σ3,whereσ1,σ2,andσ3 are the major principal stress,intermediate principal stress,and minor principal stress,respectively)is essential to the safety of underground engineering.However,in the laboratory,it is difficult to maintain the constant true triaxial stress state of rocks during the dynamic testing process.Herein,a numerical servo triaxial Hopkinson bar(NSTHB)was developed to study the dynamic responses of rocks confronted with a true triaxial stress state,in which lateral stresses can maintain constant.The results indicate that the dynamic strength and elastic modulus of rocks increase with the rise of intermediate principal stressσ2,while the dynamic elastic modulus is independent of the dynamic strain rate.Simulated acoustic emission distributions indicate that the intermediate principal stressσ2 dramatically affects dynamic failure modes of triaxial confined rocks.Asσ2 increases,the failure pattern switches from a single diagonal shear zone into two parallel shear zones with a small slant.Moreover,a recent triaxial Hopkinson bar experimental system using three bar pairs is also numerically established,and the measuring discrepancies are identified between the two numerical bar systems.The proposed NSTHB system provides a controllable tool for studying the dynamic triaxial behavior of rocks.

关键词： Triaxial Hopkinson bar Intermediate principal stress Dynamic strength Failure modes Numerical simulation True triaxial stress

Approximate Optimal Filter Design for Vehicle System through Actor‑Critic Reinforcement Learning

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Automotive Innovation 2022年第4期5卷 415-426页

作者： Yuming Yin Shengbo Eben Li Kaiming Tang Wenhan Cao wei Wu hongbo Li School of Mechanical Engineering Zhejiang University of TechnologyHangzhou 310023China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China Beijing Geekplus Tech.Co. LtdBeijingChina

Precise state and parameter estimations are essential for identification,analysis and control of vehicle engineering problems,especially under significant model and measurement uncertainties.The widely used filtering/estimation algorithms,such as Kalman series like Kalman filter,extended Kalman filter,unscented Kalman filter,and particle filter,generally aim to approach the true state/parameter distribution via iteratively updating the filter gain at each time step.However,the optimal-ity of these filters would be deteriorated by unrealistic initial condition or significant model error.Alternatively,this paper proposes to approximate the optimal filter gain by considering the effect factors within infinite time horizon,on the basis of estimation-control duality.The proposed approximate optimal filter(AOF)problem is designed and subsequently solved by actor-critic reinforcement learning(RL)method.The AOF design transforms the traditional optimal filtering problem with the minimum expected mean square error into an optimal control problem with the minimum accumulated estimation error,in which the estimation error is used as the surrogate system state and the infinite-horizon filter gain is the control input.The estimation-control duality is proved to hold when certain conditions about initial vehicle state distributions and policy structure are maintained.In order to evaluate of the effectiveness of AOF,a vehicle state estimation problem is then demonstrated and compared with the steady-state Kalman filter.The results showed that the obtained filter policy via RL with different discount factors can converge to theoretical optimal gain with an error within 5%,and the average estimation errors of vehicle slip angle and yaw rate are less than 1.5×10–4.

关键词： Vehicle state estimation Kalman filter Estimation-control duality Reinforcement learning

The role of Re in improving the oxidation-resistance of a Re modified PtAl coating on Mo-rich single crystal superalloy

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Journal of Materials Science & Technology 2020年第23期58卷 63-72页

作者： Jingchen Li Liangliang wei Jian He Hao Chen hongbo Guo School of Materials Science and Engineering Beihang UniversityBeijing100191China Research Institute for Frontier Science Beihang UniversityBeijing100191China Key Laboratory of High-Temperature Structure Materials and Protective Coatings(Ministry of Industry and Information Technology) Beihang UniversityBeijing100191China Department of Mechanical Materials and Manufacturing EngineeringFaculty of Science and EngineeringUniversity of Nottingham Ningbo ChinaNingbo315100China

A novel Re modifiedβ-(Ni,Pt)Al coating was prepared on a Mo-rich Ni_3 Al-based single crystal(SC)superalloy by electro-deposition of Re/Pt dual films and low-activity aluminizing.The isothermal oxidation behavior of the Re modifiedβ-(Ni,Pt)Al coating and traditionalβ-(Ni,Pt)Al coating was comparatively studied at 1100℃.Apparent spallation of oxide scale was found on the surface of traditionalβ-(Ni,Pt)Al coating after 300 h isothermal exposure,which mainly resulted from the evaporation of Mo-containing oxides.It is further found that the outward diffusion of Mo from the SC substrate was effectively inhibited in the Re modifiedβ-(Ni,Pt)Al coating by forming theσ-MoRe phase both at the coating/superalloy interface and grain boundaries.It is also revealed that the addition of Re can stabilise Mo to form theσ-MoRe phase,allowing the improved oxidation resistance of the Re modifiedβ-(Ni,Pt)Al coating.

关键词： Superalloy PtAl coatings Oxidation Diffusion barrier

Experimental study on broadband bistable energy harvester with L-shaped piezoelectric cantilever beam

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Acta Mechanica Sinica 2020年第3期36卷 557-577页

作者： Minghui Yao Pengfei Liu Li Ma hongbo Wang wei Zhang School of Artificial Intelligence Tiangong UniversityTianjin 300387China School of Mechanical Engineering Tiangong UniversityTianjin Key Laboratory of Modern Mechatronics Equipment TechnologyTianjin 300387China College of Mechanical Engineering Beijing University of TechnologyBeijing Key Laboratory of Nonlinear Vibrations and Strength of Mechanical StructuresBeijing 100124China

This paper presents an experimental study of the broadband energy harvesting and dynamic responses of an L-shaped piezoelectric cantilever beam.Experimental results show that the L-shaped piezoelectric beam generates two optimal voltage peaks when the horizontal beam size is similar to the vertical beam size.Several optimized L-shaped piezoelectric cantilever beam structures are proposed.Power generation using the inverted bistable L-shaped beam is better.It is observed experimentally that the inverted bistable L-shaped beam structure shows obvious bistable characteristics and hard spring characteristics.Furthermore,the corresponding relationship between the bistable phase portrait and the potential energy curve is found in the experiment.This is the first time that a phase portrait for stiffness hardening of an L-shaped beam has been found experimentally.These results can be applied to analysis of new piezoelectric power generation structures.

关键词： Bistable piezoelectric energy harvester Inverted L-shaped beam Power generation Effective frequency bandwidth Nonlinear dynamics

Estimation of the radiation backgrounds in the CEPC vertex detector

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Radiation Detection Technology and Methods 2022年第2期6卷 170-178页

作者： wei Xu Haoyu Shi hongbo Zhu Ke Li Sha Bai Xinchou Lou Institute of High Energy Physics Chinese Academy of SciencesBeijing 100049China School of Physics Zhejiang UniversityHangzhou 310058China Department of Physics University of WashingtonSeattleWA 98195USA

Background The Circular Electron-Positron Collider(CEPC)is aimed for precision measurements of the Higgs boson properties and the electroweak parameters.The achievable precision will be largely dependent on the controlled level of radiation backgrounds,which requires an optimized design of the interaction region to assure the optimal performance of both the accelerator and the detectors.Purpose In this article,the latest results on the radiation backgrounds are reported based on the accelerator parameters and the detector design presented in the CEPC conceptual design reports.Method For the different sources of radiation backgrounds,simulation steps consisting of generation,tracking,and detector simulation were performed.Radiation backgrounds from the processes of synchrotron radiation,pair production,radiative Bhabha scattering,beam gas Bremsstrahlung scattering,and beam thermal photon scattering were considered for the accel-erator operating at the different centre-of-mass energies(HZ threshold,WW threshold,and Z pole).Possible mitigation methods of masks and/or collimators were introduced to suppress the radiation backgrounds,together with the careful opti-mization of the interaction region design.With the improved tracking methods during simulation,the accuracy and reliability of the results were improved.In addition,the radiation backgrounds on the CEPC vertex detector were estimated,and the pair-production was found to be the most important source.Result In the worst case of operation at the Z pole,the vertex detector would have to withstand a total ionization dose of 5.6 Mrad per year and a non-ionization energy loss(shown in 1 MeV neutron equivalent)of 1.06×10^(13)n_(eq)/cm^(2)per year.

关键词： CEPC Interaction region Beam-induced background Vertex detector

Application of Improved Multi-Objective Ant Colony Optimization Algorithm in Ship Weather Routing

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Journal of Ocean University of China 2021年第1期20卷 45-55页

作者： ZHANG Guangyu WANG hongbo ZHAO wei GUAN Zhiying LI Pengfei State Key Laboratory on Integrated Optoelectronics College of Electronic Science and EngineeringJilin UniversityChangchun 130012China CRRC Changchun Railway Vehicles Co. Ltd.Changchun 130000China

This paper presents a novel intelligent and effective method based on an improved ant colony optimization(ACO)algorithm to solve the multi-objective ship weather routing optimization problem,considering the navigation safety,fuel consumption,and sailing time.Here the improvement of the ACO algorithm is mainly reflected in two aspects.First,to make the classical ACO algorithm more suitable for long-distance ship weather routing and plan a smoother route,the basic parameters of the algorithm are improved,and new control factors are introduced.Second,to improve the situation of too few Pareto non-dominated solutions generated by the algorithm for solving multi-objective problems,the related operations of crossover,recombination,and mutation in the genetic algorithm are introduced in the improved ACO algorithm.The final simulation results prove the effectiveness of the improved algorithm in solving multi-objective weather routing optimization problems.In addition,the black-box model method was used to study the ship fuel consumption during a voyage;the model was constructed based on an artificial neural network.The parameters of the neural network model were refined repeatedly through the historical navigation data of the test ship,and then the trained black-box model was used to predict the future fuel consumption of the test ship.Compared with other fuel consumption calculation methods,the black-box model method showed higher accuracy and applicability.

关键词： multi-objective optimization weather routing ACO algorithm fuel consumption