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A machine learning approach to query generation in plagiarism source retrieval

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Frontiers of Information Technology & Electronic Engineering 2017年第10期18卷 1556-1572页

作者： lei-lei KONG Zhi-mao LU Hao-liang QI Zhong-yuan HAN College of Information and Communication Engineering Harbin Engineering University Harbin 150001 China School of Computer Science and Technology Heilongjiang Institute of Technology Harbin 150050 China State Key Laboratory of Digital Publishing Technology Beijing 100871 China

Plagiarism source retrieval is the core task of plagiarism detection. It has become the standard for plagiarism detection to use the queries extracted from suspicious documents to retrieve the plagiarism sources. Generating queries from a suspicious document is one of the most important steps in plagiarism source retrieval. Heuristic-based query generation methods are widely used in the current research. Each heuristic-based method has its own advantages, and no one statistically outperforms the others on all suspicious document segments when generating queries for source retrieval. Further improvements on heuristic methods for source retrieval rely mainly on the experience of experts. This leads to difficulties in putting forward new heuristic methods that can overcome the shortcomings of the existing ones. This paper paves the way for a new statistical machine learning approach to select the best queries from the candidates. The statistical machine learning approach to query generation for source retrieval is formulated as a ranking framework. Specifically, it aims to achieve the optimal source retrieval performance for each suspicious document segment. The proposed method exploits learning to rank to generate queries from the candidates. To our knowledge, our work is the first research to apply machine learning methods to resolve the problem of query generation for source retrieval. To solve the essential problem of an absence of training data for learning to rank, the building of training samples for source retrieval is also conducted. We rigorously evaluate various aspects of the proposed method on the publicly available PAN source retrieval corpus. With respect to the established baselines, the experimental results show that applying our proposed query generation method based on machine learning yields statistically significant improvements over baselines in source retrieval effectiveness.

关键词： Plagiarism detection Source retrieval Query generation Machine learning Learning to rank

Spiral wave chimeras in populations of oscillators coupled to a slowly varying diffusive environment

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Frontiers of physics 2023年第1期18卷 71-83页

作者： lei Yang yuan He Bing-Wei Li School of Physics Hangzhou Normal UniversityHangzhou 311121China

Chimera states are firstly discovered in nonlocally coupled oscillator *** a nonlocal coupling arises typically as oscillators are coupled via an external environment whose characteristic time scaleτis so small(i.e.,τ→0)that it could be eliminated ***,whether the chimera states still exist in the opposite situation(i.e.,τ≫1)is ***,by coupling large populations of Stuart–Landau oscillators to a diffusive environment,we demonstrate that spiral wave chimeras do exist in this oscillator-environment coupling system even whenτis very *** transitions such as from spiral wave chimeras to spiral waves or unstable spiral wave chimeras as functions of the system parameters are explored.A physical picture for explaining the formation of spiral wave chimeras is also *** existence of spiral wave chimeras is further confirmed in ensembles of FitzHugh–Nagumo oscillators with the similar oscillator-environment coupling *** results provide an affirmative answer to the observation of spiral wave chimeras in populations of oscillators mediated via a slowly changing environment and give important hints to generate chimera patterns in both laboratory and realistic chemical or biological systems.

关键词： spiral wave chimeras reaction-diffusion systems oscillator-environment coupling pattern formation

Multiphysics simulation method of Lamb wavepropagation with piezoelectric transducers under load condition

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Chinese Journal of Aeronautics 2019年第5期32卷 1071-1086页

作者： lei QIU Xixi YAN Xiaodong LIN Shenfang yuan Research Center of Structural Health Monitoring and Prognosis State Key Lab of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and Astronautics

Lamb Wave(LW) simulation under time-varying conditions is an effective and low cost way to study the problem of the low reliability of the structural health monitoring methods based on the LW and Piezoelectric Transducer(PT). In this paper, a multiphysics simulation method of the LW propagation with the PTs under load condition is proposed. With this method, two key mechanisms of the load influence on the LW propagation are considered and coupled with each other. The first mechanism is the acoustoelastic effect which is the main reason of the LW velocity change. The second key mechanism is the load influence on piezoelectric materials, which results in a change of the amplitude. Based on the computational platform of the COMSOL Multiphysics, a multiphysics simulation model of the LW propagation with the PTs under load condition is established. The simulation model includes two physical phenomena. The first one is called solid mechanics, which is used to simulate the acoustoelastic effect being combined with the hyperelastic material properties of the structure in which the LW propagates. The second one is called electromechanical coupling, which considers the simulation of the piezoelectric effect of the PTs for the LW excitation and sensing. To simulate the load influence on piezoelectric materials, a non-linear numerical model of the relationship between the load and the piezoelectric coefficient d31 is established based on an experiment of the load influence on the LW. The simulation results under uniaxial tensile load condition are obtained and are compared with the data obtained from the experiment. It shows that the variations of the phase velocity and amplitude of the LW obtained from the simulation model match the experimental results well.

关键词： Acoustoelastic effect Lamb wave Multiphysics simulation Piezoelectric coefficient Structural health monitoring Time-varying condition

Improved virtual synchronous control for grid-connected VSCs under grid voltage unbalanced conditions

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Journal of Modern Power Systems and Clean Energy 2019年第1期7卷 174-185页

作者： lei SHANG Jiabing HU Xiaoming yuan Yunhui HUANG Huazhong University of Science and Technology Wuhan University of Technology

This paper presents an improved virtual synchronous control(VSynC) for the grid-connected voltage source converter(VSC) so as to continuously operate under the grid voltage with steady *** improved VSynC introduces the negative sequence power controls on basis of conventional *** improved VSynC is capable of regulating the negative sequence internal voltage to reduce the negative-sequence injected currents and oscillated powers of the VSC aroused by the negative-sequence grid *** alternative local control objectives for the VSC itself under steady state unbalanced grid conditions and their corresponding power references are deduced and *** and experimental results are presented to validate the correctness and effectiveness of the proposed improved VSynC to enhance the continuous operation performance of VSynC-based VSCs during grid voltage steady-state unbalance.

关键词： Grid voltage unbalance Virtual synchronous control(VSynC) Grid-connected voltage source converter(VSC)

Adaptive Multi-Bernoulli Filter Without Need of Prior Birth Multi-Bernoulli Random Finite Set

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Chinese Journal of Electronics 2018年第1期27卷 115-122页

作者： yuan Changshun WANG Jun lei Peng SUN Jinping School of Electronic and Information Engineering Beihang University

Conventional Multi-Bernoulli(MBer) filter assumes that the birth MBer Random finite set(RFS)is known a priori. However, this is not true for practical scenario. This paper proposes a novel extension of the MBer filter which eliminates the reliance of the prior birth MBer RFS and relaxes the limitation in new-born target appearance volume. The proposed filter classifies the measurements into survival measurements and birth measurements, and adaptively generates the birth MBer RFS using the birth measurements. The novel filtering equations that distinguish the persistent and new-born targets are derived. A Sequential Monte-Carlo(SMC) implementation of the proposed filter is given. Simulations are performed to verify the improvement in the performance of the proposed filter.

关键词： Random finite set Adaptive multi-Bernoulli filter Sequential Monte-Carlo Multi-target tracking

Feature-Grounded Single-Stage Text-to-Image Generation

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Tsinghua Science and Technology 2024年第2期29卷 469-480页

作者： yuan Zhou Peng Wang lei Xiang Haofeng Zhang School of Artificial Intelligence Nanjing University of Information Science and TechnologyNanjing 210044China School of Computer Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China

Recently,Generative Adversarial Networks(GANs)have become the mainstream text-to-image(T2I)***,a standard normal distribution noise of inputs cannot provide sufficient information to synthesize an image that approaches the ground-truth image ***,the multistage generation strategy results in complex T2I ***,this study proposes a novel feature-grounded single-stage T2I model,which considers the“real”distribution learned from training images as one input and introduces a worst-case-optimized similarity measure into the loss function to enhance the model's generation *** results on two benchmark datasets demonstrate the competitive performance of the proposed model in terms of the Frechet inception distance and inception score compared to those of some classical and state-of-the-art models,showing the improved similarities among the generated image,text,and ground truth.

关键词： text-to-image(T2I) feature-grounded single-stage generation Generative Adversarial Network(GAN)

Communication-robust multi-agent learning by adaptable auxiliary multi-agent adversary generation

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Frontiers of Computer Science 2024年第6期18卷 186331-186331页

作者： yuan lei CHEN Feng ZHANG Zongzhang YU Yang National Key Laboratory for Novel Software Technology Nanjing University Polixir Technologies

Communication can promote coordination in cooperative Multi-Agent Reinforcement Learning (MARL). Nowadays, existing works mainly focus on improving the communication efficiency of agents, neglecting that real-world communication is much more challenging as there may exist noise or potential attackers. Thus the robustness of the communication-based policies becomes an emergent and severe issue that needs more exploration. In this paper, we posit that the ego system trained with auxiliary adversaries may handle this limitation and propose an adaptable method of Multi-Agent Auxiliary Adversaries Generation for robust Communication, dubbed MA3C, to obtain a robust communication-based policy. In specific, we introduce a novel message-attacking approach that models the learning of the auxiliary attacker as a cooperative problem under a shared goal to minimize the coordination ability of the ego system, with which every information channel may suffer from distinct message attacks. Furthermore, as naive adversarial training may impede the generalization ability of the ego system, we design an attacker population generation approach based on evolutionary learning. Finally, the ego system is paired with an attacker population and then alternatively trained against the continuously evolving attackers to improve its robustness, meaning that both the ego system and the attackers are adaptable. Extensive experiments on multiple benchmarks indicate that our proposed MA3C provides comparable or better robustness and generalization ability than other baselines.

关键词： multi-agent communication adversarial training robustness validation reinforcement learning

The Game Theoretical Approach for Multi-phase Complex Systems in Chemical Engineering

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Journal of Systems Science & Complexity 2017年第1期30卷 4-19页

作者： LI Yan MU Yifen yuan Shuo GUO lei Beijing National Day School Beijing 100039 China Key Lab of Systems and Control Institute of Systems Science Academy of Mathematics and Systems ScienceChinese Academy of Sciences Beijing 100190 China

This paper explores the application of noncooperative game theory together with the concept of Nash equilibrium to the investigation of some basic problems on multi-scale structure, especially the meso-scale structure in the multi-phase complex systems in chemical engineering. The basis of this work is the energy-minimization-multi-scale （EMMS） model proposed by Li and Kwauk （1994） and Li, et al. （2013） which identifies the multi-scale structure as a result of ＇compromise-in-competition between dominant mechanisms＇ and tries to solve a multi-objective optimization problem. However, the existing methods often integrate it into a problem of single objective optimization, which does not clearly reflect the ＇compromise-in-competition＇ mechanism and causes heavy computation burden as well as uncertainty in choosing suitable weighting factors. This paper will formulate the compromise in competition mechanism in EMMS model as a noncooperative game with constraints, and will describe the desired stable system state as a generalized Nash equilibrium. Then the authors will investigate the game theoretical approach for two typical systems in chemical engineering, the gas-solid fluidiza- tion （GSF） system and turbulent flow in pipe. Two different cases for generalized Nash equilibrinm in such systems will be well defined and distinguished. The generalize Nash equilibrium will be solved accurately for the GSF system and a feasible method will be given for turbulent flow in pipe. These results coincide with the existing computational results and show the feasibility of this approach, which overcomes the disadvantages of the existing methods and provides deep insight into the mechanisms of multi-scale structure in the multi-phase complex systems in chemical engineering.

关键词： Game theory gas-solid fluidization generalized Nash equilibrium multi-phase complexsystems turbulent flow.

Fully Distributed Resilient Cooperative Control of Vehicular Platoon Systems Under DoS Attacks

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IEEE/CAA Journal of Automatica Sinica 2022年第5期9卷 937-940页

作者： lei Ding Jie Li Maojiao Ye yuan Zhao Institute of Advanced Technology Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Automation Nanjing University of Science and TechnologyNanjing 210094China College of Information Engineering Dalian UniversityDalian 116622China IEEE

Dear Editor,This letter is concerned with distributed resilient platoon control of multiple vehicles subject to denial-of-service(DoS)*** order to accommodate the effects of DoS attacks,a fully resilient distributed control strategy is presented by designing an adaptive control gain,where any global information of communication topology is no longer ***,the conditions of time duration rates and frequency of DoS attacks on stability of vehicular platoons can be ***,a numerical simulation example is given to validate the obtained results.

关键词： DoS service designing