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A New Efficient Certificate-Based Signature Scheme

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Chinese Journal of Electronics 2015年第4期24卷 776-782页

作者： zhang yichen LI Jiguo WANG Zhiwei YAO Wei College of Computer and Information Hohai University

Certificate-based cryptography is a new kind of public key algorithm, which combines the merits of traditional Public key infrastructure(PKI) and identitybased cryptography. It removes the inherent key escrow problem in the identity-based cryptography and eliminates the certificate revocation problem and third-party queries in the traditional PKI. In this paper, we propose an efficient certificate-based signature scheme based on bilinear pairings. Under the strong security model of certificatebased signature scheme, we prove that our scheme is existentially unforgeable against adaptive chosen message and identity attacks in the random oracle. In our scheme, only two pairing operations are needed in the signing and verification processes. Compared with some certificate-based signature schemes from bilinear pairings, our scheme enjoys more advantage in computational cost and communicational cost.

关键词： Certificate-based signature Random oracle model Provable security Bilinear pairings

Continuous-Variable Measurement-Device-Independent Quantum Key Distribution with One-Time Shot-Noise Unit Calibration

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Chinese Physics Letters 2021年第4期38卷 1-6页

作者： Luyu Huang yichen zhang Song Yu State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and TelecommunicationsBeijing 100876China

Imperfections in practical detectors,including limited detection efficiency,and inherent electronic noise,can seriously decrease the transmission distance of continuous-variable measurement-device-independent quantum key distribution *** to the difficulties inherent in realizing a high-efficiency fiber homodyne detector,challenges still exist in continuous-variable measurement-device-independent quantum key distribution system *** offer an alternative approach in an attempt to solve these difficulties and improve the potential for system ***,a novel practical detector modeling method is utilized,which is combined with a one-time shot-noise-unit calibration method for the purpose of system *** new modeling method benefits greatly from taking advantage of one-time shot-noise-unit calibration methods,such as measuring electronic noise and shot noise directly to a novel shot-noise unit,so as to eliminate the statistical fluctuations found in previous methods;this makes the implementation of such systems simpler,and the calibration progress more *** provide a simulation of the secret key rate versus distance with different *** addition,the minimal detection efficiency required at each distance,as well as the contrast between the two methods,are also shown,so as to provide a reference in terms of system realization.

关键词： realization Independent eliminate

Effects of Varying Copper Content on the Microstructure and Mechanical Properties of FeCoNiCu_(x)

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Journal of Wuhan University of Technology(Materials Science) 2022年第5期37卷 986-991页

作者： YANG Yanru zhang yichen LI Jiawen ZHU Heguo College of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing210094China

Five sets of high entropy alloys(HEAs)FeCoNiCu_(x)(x=0.5,1.0,1.5,2.0,2.5)were produced by vacuum induction *** effects of Cu content on the microstructure and mechanical properties of the alloys were interrogated by X-ray diffractometer(XRD),field scanning electron microscope(FESEM)and tensile mechanical *** result shows that the HEAs form single FCC solid solution *** the increase of Cu content,the diffraction peak first deviated to the right and then shifted to the *** alloys changed from equiaxed crystal structure to refined dendritic crystal structure,as Cu content increased.A large number of Cu atoms are isolated in the inter-crystalline *** tensile mechanical tests show that with the increase of Cu content,the ultimate tensile strength first increased and then *** x is 2.0,the ultimate tensile strength reaches a maximum of 473 MPa,the percent elongation is 43.0%,and the fracture presents ductile behaviour.

关键词： FeCoNiCu alloy copper content microstructure elemental segregation mechanical properties

Distributed algorithm for solving variational inequalities over time-varying unbalanced digraphs

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Control Theory and Technology 2024年第3期22卷 431-441页

作者： yichen zhang Yutao Tang Zhipeng Tu Yiguang Hong School of Artificial Intelligence Beijing University of Posts and TelecommunicationsBeijing 100876China Network Technology Laboratory Huawei Technologies Co.Ltd.Beijing 100095China Department of Control Science and Engineering Tongji UniversityShanghai 200092China Shanghai Research Institute for Intelligent Autonomous Systems Tongji UniversityShanghai 200092China

In this paper,we study a distributed model to cooperatively compute variational inequalities over time-varying directed ***,each agent has access to a part of the full mapping and holds a local view of the global set *** virtue of an auxiliary vector to compensate the graph imbalance,we propose a consensus-based distributed projection algorithm relying on local computation and communication at each *** show the convergence of this algorithm over uniformly jointly strongly connected unbalanced digraphs with nonidentical local *** also provide a numerical example to illustrate the effectiveness of our algorithm.

关键词： Variational inequality Distributed computation Multi-agent system Weight-unbalanced graph

Deep Active Learning for Solvability Prediction in Power Systems

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Journal of Modern Power Systems and Clean Energy 2022年第6期10卷 1773-1777页

作者： yichen zhang Jianzhe Liu Feng Qiu Tianqi Hong Rui Yao Argonne National Laboratory LemontIL 60439USA IEEE

Traditional methods for solvability region analysis can only have inner approximations with inconclusive conservatism and handle limited types of power flow *** this letter,we propose a deep active learning framework for solvability prediction in power *** with passive learning where the training is performed after all instances are labeled,active learning selects most informative instances to be labeled and therefore significantly reduces the size of the labeled dataset for *** the active learning framework,the acquisition functions,which correspond to different sampling strategies,are defined in terms of the on-the-fly posterior probability from the ***,the IEEE 39-bus system is employed to validate the proposed framework,where a two-dimensional case is illustrated to visualize the effectiveness of the sampling method followed by the high-dimensional numerical ***,the Northeast Power Coordinating Council(NPCC)140-bus system is used to validate the performance on large-scale power systems.

关键词： Active learning deep learning power flow solvability power flow equation

Accelerated initiation of oblique detonation induced by disturbance in detonative zone

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Chinese Journal of Aeronautics 2023年第11期36卷 153-164页

作者： yichen zhang Gaoxiang XIANG Jia YU Ke JIN Kek Boon GOH Institute of Extreme Mechanics Northwestern Polytechnical UniversityXi’an 710129China Research and Development Institute Northwestern Polytechnical University in ShenzhenShenzhen 518057China Innovation Center NPU Chongqing Northwestern Polytechnical UniversityChongqing 401135China School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Department of Mechanical Engineering School of EngineeringMonash University MalaysiaSelangor 47500Malaysia

In the real flow for high altitude,the initiation mechanism of the oblique detonation involves the coupling of complex wave structures and combustion waves,which may result in the phenomenon of *** approach of stable initiation is one of the key factors that restricting the oblique detonation engine from theory to *** wave structure,initiation characteristics and characteristic parameters of the flow field are analyzed,the two-dimensional Euler equation considering the detailed chemical reactions of multi-component are ***,the approaches of blunt bump and transverse jet are combined used to shorten the detonation distance of the oblique *** show that these methods can promote the accelerated initiation of the oblique detonation effectively,and the detonation distance can be shortened more than 90%.There are two wave structures induced by the blunt bump:weak coupled and strong coupled,adding the transverse jet promotes the transition between these two wave ***,the shape of the bump and the characteristic parameters of the transverse jet are *** streamline-shape bump can eliminate the recirculation zone formed after the circle bump and the ellipse *** transverse jet will produce an oblique detonation wave at the front of the jet position,which changes the wave structure and initiation mode of the oblique detonation *** is expected to reveal the accelerated initiation mechanism of oblique detonation under the induction zone disturbance and complex flow environment,deepen the understanding of the detonation law of oblique detonation wave under real flow conditions,and provide a scientific basic for the development of the combustor of the oblique detonation engine.

关键词： Acetylene Oblique detonation Initiation acceleration Blunt bump Transverse jet Numerical simulation

Virtual Power Plants for Grid Resilience: A Concise Overview of Research and Applications

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IEEE/CAA Journal of Automatica Sinica 2024年第2期11卷 329-343页

作者： Yijing Xie yichen zhang Wei-Jen Lee Zongli Lin Yacov A.Shamash IEEE Department of Electrical Engineering University of Texas at ArlingtonArlingtonTX 76019 USA Charles L.Brown Department of Electrical and Computer Engineering University of VirginiaCharlottesvilleVA 22904 USA Department of Electrical and Computer Engineering Stony Brook UniversityStony BrookNY 11794 USA

The power grid is undergoing a transformation from synchronous generators(SGs) toward inverter-based resources(IBRs). The stochasticity, asynchronicity, and limited-inertia characteristics of IBRs bring about challenges to grid resilience. Virtual power plants(VPPs) are emerging technologies to improve the grid resilience and advance the transformation. By judiciously aggregating geographically distributed energy resources(DERs) as individual electrical entities, VPPs can provide capacity and ancillary services to grid operations and participate in electricity wholesale markets. This paper aims to provide a concise overview of the concept and development of VPPs and the latest progresses in VPP operation, with the focus on VPP scheduling and control. Based on this overview, we identify a few potential challenges in VPP operation and discuss the opportunities of integrating the multi-agent system(MAS)-based strategy into the VPP operation to enhance its scalability, performance and resilience.

关键词： Climate change renewable energy resources resilience smart grids virtual power plants(VPPs)

Population amount risk assessment of extreme precipitation-induced landslides based on integrated machine learning model and scenario simulation

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Geoscience Frontiers 2023年第3期14卷 163-179页

作者： Guangzhi Rong Kaiwei Li Zhijun Tong Xingpeng Liu Jiquan zhang yichen zhang Tiantao Li School of Environment Northeast Normal UniversityChangchun 130024China Key Laboratory for Vegetation Ecology Ministry of EducationChangchun 130117China State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration Northeast Normal UniversityChangchun 130117China School of Emergency Management Changchun Institute of TechnologyChangchun 130012China Chengdu University of Technology Chengdu 610059China State Key Laboratory of Geohazard Prevention and Geo Environment Protection Chengdu University of TechnologyChengdu 610059China

In this study,the future landslide population amount risk(LPAR)is assessed based on integrated machine learning models(MLMs)and scenario simulation techniques in Shuicheng County,***,multiple MLMs were selected and hyperparameters were optimized,and the generated 11 models were crossintegrated to select the best model to calculate landslide susceptibility;by calculating precipitation for different extreme precipitation recurrence periods and combining the susceptibility results to assess the landslide *** the town as the basic unit,the exposure and vulnerability of the future landslide population under different Shared Socioeconomic Pathways(SSPs)scenarios in each town were assessed,and then combined with the hazard to estimate the LPAR in *** results showed that the integrated model with the optimized random forest model as the combination strategy had the best comprehensive performance in susceptibility *** distribution of hazard classes is similar to susceptibility,and with an increase in precipitation,the low-hazard area and high-hazard decrease and shift to medium-hazard and very high-hazard *** high-risk areas for future landslide populations in Shuicheng County are mainly concentrated in the three southwestern towns with high vulnerability,whereas the northern towns of Baohua and Qinglin are at the lowest risk *** LPAR increased with the intensity of extreme *** LPAR differs significantly among the SSPs scenarios,with the lowest in the“fossil-fueled development(SSP5)”scenario and the highest in the“regional rivalry(SSP3)”*** summary,the landslide susceptibility model based on integrated machine learning proposed in this study has a high predictive *** results of future LPAR assessment can provide theoretical guidance for relevant departments to cope with future socioeconomic development challenges and make corresponding disaster prevention and mitigation plans to prevent landsli

关键词： Landslide population amount risk assessment Integrated Machine Learning Extreme precipitation scenarios Future socioeconomic development scenarios

Practical continuous-variable quantum key distribution with feasible optimization parameters

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Science China(Information Sciences) 2023年第8期66卷 80-91页

作者： Li MA Jie YANG Tao zhang Yun SHAO Jinlu LIU Yujie LUO Heng WANG Wei HUANG Fan FAN Chuang ZHOU Liangliang zhang Shuai zhang yichen zhang Yang LI Bingjie XU Science and Technology on Communication Security Laboratory Institute of Southwestern Communication State Key Laboratory of Information Photonics and Optical Communications Beijing University of Posts and Telecommunications

Continuous-variable quantum key distribution(CV-QKD) offers an approach to achieve a potential high secret key rate(SKR) in metropolitan areas. There are several challenges in developing a practical CV-QKD system from the laboratory to the real world. One of the most significant points is that it is really hard to adapt different practical optical fiber conditions for CV-QKD systems with unified hardware. Thus,how to improve the performance of practical CV-QKD systems in the field without modification of the hardware is very important. Here, a systematic optimization method, combining the modulation variance and error correction matrix optimization, is proposed to improve the performance of a practical CV-QKD system with a restricted capacity of postprocessing. The effect of restricted postprocessing capacity on the SKR is modeled as a nonlinear programming problem with modulation variance as an optimization parameter,and the selection of an optimal error correction matrix is studied under the same scheme. The results show that the SKR of a CV-QKD system can be improved by 24% and 200% compared with previous frequently used optimization methods theoretically with a transmission distance of 50 km. Furthermore, the experimental results verify the feasibility and robustness of the proposed method, where the achieved optimal SKR achieved practically deviates <1.6% from the theoretical optimal value. Our results pave the way to deploy high-performance CV-QKD in the real world.

关键词： continuous-variable quantum key distribution post-processing optimization secret key rate