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Chinese Annals of Mathematics,Series B 2018年第6期39卷 947-962页

作者： lei yu School of Mathematical Sciences Tongji University Shanghai 200092 China

This paper proves the local exact one-sided boundary null controllability of entropy solutions to a class of hyperbolic systems of conservation laws with characteristics with constant multiplicity. This generalizes the results in [Li, T. and yu, L., One-sided exact boundary null controllability of entropy solutions to a class of hyperbolic systems of conservation laws, To appear in Journal de Mathematiques Pures et Appliquees, 2016.] for a class of strictly hyperbolic systems of conservation laws.

关键词： Characteristics with constant multiplicity One-sided boundary null controllability Semi-global entropy solution ε-Approximate front tracking solution

Ground-level ozone(O 3)pollution and its impacts on vegetation:an attribute to *** Agathokleous

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Journal of Forestry Research 2023年第3期34卷 577-578页

作者： lei yu The Editorial Board of Journal of Forestry Research Northeast Forestry UniversityHarbin 150040People’s Republic of China

The Journal of Forestry Research(JFR)is pleased to highlight a collection of ten papers published by *** Agathokleous and colleagues in 2020–*** recognition of the current heightened attention into ground-level ozone(O 3)pollution and its impacts on vegetation,this collection addresses eff ects of ozone on plants,methods to counteract plant stress eff ects,and assessment of potential ozone risks.

关键词： pollution ozone collection

Structure and electrical properties of (1-x)BaTiO_3+(x)La_(2/3)-Sr_(1/3)MnO_3 composites

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Acta Metallurgica Sinica(English Letters) 2011年第4期24卷 315-320页

作者： Zhengyou ZHOU yu lei School of Materials Science and Engineering Nanchang University Nanchang 330031 China College of Vocational Education East China Jiaotong University Nanchang 330031 China

Liquid-phase sintering method was used to prepare BaTiO3 powders and the struc- ture and electrical properties of （1-x）BaTiO3-]-（x）La2/3Srl/3Mn03 （LSMO） compos- ites were investigated. The results of X-ray diffraction showed that the prepared BaTiO3 powders were pure and fine, indicating that sintering temperature was effec- tively lowered when the NaC1 sintering aid was added. X-ray diffraction patterns of （1-x）BaTiO3＋（x）La2/3Srl/3Mn03 （LSMO） composites showed that LSMO and BaTiO3 phases were coexistent and no other phases were detected. The impedance spectra showed that the resistance of grain boundaries for LSMO-doped samples was suppressed. The resistivity-temperature measurements showed that room- temperature resistivity of the composites was lowered from insulator for pure BaTiO3 ceramic to 103 ~.m for the x----0.3 sample. The sample of x_〈0.2 showed the positive temperature coefficient （PTC） effect whereas the x=0.3 sample exhibited PTC effect at temperatures below 68 ~C and then negative temperature coefficient （NTC） effect at temperatures above 68 ~C. The related mechanism has been elucidated.

关键词： Positive temperature coefficient Composite Impedance spectra Resistivity

Six statistical issues in scientific writing that might lead to rejection of a manuscript

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Journal of Forestry Research 2022年第3期33卷 731-739页

作者： Evgenios Agathokleous lei yu School of Applied Meteorology Nanjing University of Information Science and Technology(NUIST)Nanjing210044People’s Republic of China The Editorial Board of Journal of Forestry Research Northeast Forestry UniversityHarbin150040People’s Republic of China

Communication plays an important role in advancing scientific fields and disciplines,defining what knowledge is made accessible to the public,and guiding policymaking and regulation of public authorities for the benefit of the environment and ***,what is finally published is of great importance for scientific advancement,social development,environmental and public health,and economic *** recognition of these,the goal of a researcher is to communicate research findings to the scientific community and ultimately,to the ***,this may often be challenging due to competition for publication space,although to a lesser extent nowadays that online-only publications have *** editorial introduces six statistics-related issues in scientific writing that you should be aware *** issues can lead to desk rejection or rejection following a peer review,but even if papers containing such issues are published,they may prevent cumulative science,undermine scientific advancement,mislead the public,and result in incorrect or weak policies and ***,addressing these issues from the early research stages can facilitate scientific advancement and prevent rejection of your paper.

关键词： Journal editor Peer review Rejection Science communication Scientific writing

Deep kernel extreme learning machine classifier based on the improved sparrow search algorithm

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The Journal of China Universities of Posts and Telecommunications 2024年第3期31卷 15-29页

作者： Zhao Guangyuan lei yu School of Automation Xi'an University of Posts and TelecommunicationsXi'an 710000China

In the classification problem,deep kernel extreme learning machine(DKELM)has the characteristics of efficient processing and superior performance,but its parameters optimization is *** improve the classification accuracy of DKELM,a DKELM algorithm optimized by the improved sparrow search algorithm(ISSA),named as ISSA-DKELM,is proposed in this *** at the parameter selection problem of DKELM,the DKELM classifier is constructed by using the optimal parameters obtained by ISSA *** order to make up for the shortcomings of the basic sparrow search algorithm(SSA),the chaotic transformation is first applied to initialize the sparrow ***,the position of the discoverer sparrow population is dynamically adjusted.A learning operator in the teaching-learning-based algorithm is fused to improve the position update operation of the ***,the Gaussian mutation strategy is added in the later iteration of the algorithm to make the sparrow jump out of local *** experimental results show that the proposed DKELM classifier is feasible and effective,and compared with other classification algorithms,the proposed DKELM algorithm aciheves better test accuracy.

关键词： deep kernel extreme learning machine(DKELM) improved sparrow search algorithm(ISSA) classifier parameters optimization

Feature extraction of wood-hole defects using wavelet-based ultrasonic testing

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Journal of Forestry Research 2017年第2期28卷 395-402页

作者： Huiming Yang lei yu Northeast Forestry University Harbin 150040People's Republic of China

The primary bottleneck to extracting wood defects during ultrasonic testing is the accuracy of identifying the wood defects. The wavelet energy moment was used to extract defect features of artificial wood holes drilled into 120 elm samples that differed in the number of holes to verify the validity of the method. Wavelet energy moment can reflect the distribution of energy along the time axis and the amount of energy in each frequency band,which can effectively extract the energy distribution characteristics of signals in each frequency band; therefore,wavelet energy moment can replace the wavelet frequency band energy and constitute wood defect feature vectors. A principal component analysis was used to normalize and reduce the dimension of the feature vectors. A total of 16 principal component features were then obtained, which can effectively extract the defect features of the different number of holes in the elm samples.

关键词： wavelet defects ultrasonic extracting replace validity identifying verify processed bottleneck

Effect size in papers published by the Journal of Forestry Research:A missing treasure?

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Journal of Forestry Research 2023年第2期34卷 297-299页

作者： Evgenios Agathokleous lei yu School of Applied Meteorology Nanjing University of Information Science and Technology(NUIST)Nanjing 210044People’s Republic of China The Editorial Board of Journal of Forestry Research Northeast Forestry UniversityHarbin 150040People’s Republic of China

P values based on standard hypothesis testing are commonly reported in articles published by the Journal of Forestry Research(JFR).However,effect sizes are barely used and reported,even if they are of direct relevance to the primary questions of many of the published *** incorporation of effect sizes in studies published by JFR should be encouraged and *** of effect sizes as a requirement in the journal guidelines will facilitate a major change in the way data are tested and interpreted,with the ultimate goal to exempt researchers from the custom of drawing conclusions merely based upon a dichotomous statistical result(P value).Such a policy can also lead to more informed decisions of whether identified effects are of practical relevance to the forestry.

关键词： Eff ect magnitude Null hypothesis signifi cance testing P value Science communication Scientifi c writing

A Smart Obfuscation Approach to Protect Software in Cloud

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Computers, Materials & Continua 2023年第9期76卷 3949-3965页

作者： lei yu yucong Duan Department of Computer Science Inner Mongolia UniversityHohhotChina Department of Computer Science Hainan UniversityHaikouChina

Cloud computing and edge computing brought more software,which also brought a new danger of malicious software *** synchronization mechanisms of software can further help reverse data *** on the mechanisms,attackers can cover themselves behind the network and modify data *** knowledge of software reverse engineering can be organized as rules to accelerate the attacks,when attackers intrude cloud server to access the source or binary ***,we proposed a novel method to resist this kind of reverse engineering by breaking these *** method is based on software obfuscations and encryptions to enhance the security of distributed software and cloud services in the 5G *** method is capable of(1)replacing theoriginal assembly codes of theprotectedprogramwithequivalent assembly instructions inan iteration way,(2)obfuscating the control flow of the protected program to confuse attackers meanwhile keeps the program producing the same outputs,(3)encrypting data to confuse *** addition,the approach can periodically and automatically modify the protected software binary codes,and the binary codes of the protected software are encrypted to resist static analysis and dynamic ***,a simplified virtual machine is implemented to make the protected codes unreadable to *** game is one of the specific scenarios which needs low latency and strong data *** engine,Ollydbg,and Interactive Disassembler Professional(IDA)are used prevalently for *** improved methods can protect the software from the most vulnerable *** improved dynamic code swapping and the simplified virtual machine technologies for cloud games are the main *** inductively learned that our methods have been working well according to the security mechanisms and time complexity *** show that hidden dangers can be eliminated with efficient methods:Execution time and file sizes of

关键词： Obfuscation self-modification encryption edge computing

Codegree Threshold for Tiling k-graphs with Two Edges Sharing Exactly l Vertices

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Acta Mathematica Sinica,English Series 2020年第1期36卷 13-20页

作者： lei yu Xin Min HOU Key Laboratory of Wu Wen-Tsun Mathematics School of Mathematical Sciences University of Science and Technology of China

Given integer k and a k-graph F,let t(k-1)(n,F)be the minimum integer t such that every k-graph H on n vertices with codegree at least t contains an *** integers k>3 and 0≤l≤k-1,let y(k,l)be a k-graph with two edges that shares exactly l *** and Zhao(*** Ser.A,(2015))asked the following question:For all k≥3,0≤l≤k-1 and sufficiently large n divisible by 2 k-l,determine the exact value of t_(k-1)(n,y(k,l)).In this paper,we show that t(k-1)(n,y(k,l))=n/(2 k-l)for k>3 and 1≤l≤k-2,combining with two previously known results of R?dl,Rucinski and Szemeredi(*** Ser.A,(2009))and Gao,Han and Zhao(Combinatorics,Probability and Computing,(2019)),the question of Han and Zhao is solved completely.

关键词： Hypergraph codegree factor

Computation of the stability derivatives via CFD and the sensitivity equations

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Acta Mechanica Sinica 2011年第2期27卷 179-188页

作者： Guo-Dong lei yu-Xin Ren Department of Engineering Mechanics Tsinghua University 100084 Beijing China

The method to calculate the aerodynamic stability derivates of aircrafts by using the sensitivity equations is ex- tended to flows with shock waves in this paper. Using the newly developed second-order cell-centered finite volume scheme on the unstructured-grid, the unsteady Euler equations and sensitivity equations are solved simultaneously in a non-inertial frame of reference, so that the aerodynamic stability derivatives can be calculated for aircrafts with complex geometries. Based on the numerical results, behavior of the aerodynamic sensitivity parameters near the shock wave is discussed. Furthermore, the stability derivatives are analyzed for supersonic and hypersonic flows. The numerical results of the stability derivatives are found in good agree- ment with theoretical results for supersonic flows, and variations of the aerodynamic force and moment predicted by the stability derivatives are very close to those obtained by CFD simulation for both supersonic and hypersonic flows.

关键词： Aerodynamic stability derivatives Non-inertial frame of reference unstructured-grid Finite volume scheme Sensitivity equations