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A GNSS Anti-Spoofing Technique Based on the Spatial Distribution Characteristic of the Residual Vectors

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Tsinghua Science and Technology 2024年第2期29卷 457-468页

作者： Qi'an wu Xiaowei Cui Mingquan Lu Pengxiang Yang Peng wu Department of Electronic Enginnering Tsinghua UniversityBeijing 100084China Xi’an Modern Control Technology Research Institute Xi’an 710065China

Anti-spoofing is becoming a crucial technique for applications with high navigation accuracy and reliability ***-spoofing technique based on Receiver Autonomous Integrity Monitoring(RAIM)is a good choice for most Global Navigation Satellite System(GNSS)receivers because it does not require any change to the hardware of the ***,the conventional RAIM method can only detect and mitigate a single spoofing *** improved RAIM methods can deal with more spoofing signals,but the computational complexity increases dramatically when the number of satellites in view increase or need additional *** paper proposes a new RAIM method,called the SRV-RAIM method,which has a very low computation complexity regardless of the number of satellites in view and can deal with any number of spoofing *** key to the new method is the spatial distribution characteristic of the Satellites'Residual Vectors(SRV).In replay or generative spoofing scenarios,the pseudorange measurements of spoofing signals are consistent,the residual vectors of real satellites and those of spoofing satellites have good separation characteristics in spatial *** on this characteristic,the SRV-RAIM method is proposed,and the simulation results show that the method can separate the real signals and the spoofing signals with an average probability of 86.55%in the case of 12 visible satellites,regardless of the number of spoofing *** to the conventional traversal-RAIM method,the performance is only reduced by 3.59%,but the computational cost is reduced by 98.3%,so most of the GNSS receivers can run the SRV-RAIM algorithm in time.

关键词： Global Navigation Satellite System(GNSS) anti-spoofing Receiver Autonomous Integrity Monitoring(RAIM) Satellites'Residual Vectors(SRV)

Effective Identity Authentication Based on Multiattribute Centers for Secure Government Data Sharing

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Tsinghua Science and Technology 2024年第3期29卷 736-752页

作者： Meiquan Wang Junhua wu Tongdui Zhang Junhao wu Guangshun Li School of Computer Science Qufu Normal UniversityRizhao 276800China Science and Technology Innovation Service Institution of Rizhao Rizhao 276800China

As one of the essential steps to secure government data sharing,Identity Authentication(IA)plays a vital role in the processing of large ***,the centralized IA scheme based on a trusted third party presents problems of information leakage and single point of failure,and those related to key ***,herein,an effective IA model based on multiattribute centers is ***,a private key of each attribute of a data requester is generated by the attribute authorization *** obtaining the private key of attribute,the data requester generates a personal private ***,a dynamic key generation algorithm is proposed,which combines blockchain and smart contracts to periodically update the key of a data requester to prevent theft by external attackers,ensure the traceability of IA,and reduce the risk of privacy ***,the combination of blockchain and interplanetary file systems is used to store attribute field information of the data requester to further reduce the cost of blockchain information storage and improve the effectiveness of information *** results show that the proposed model ensures the privacy and security of identity information and outperforms similar authentication models in terms of computational and communication costs.

关键词： blockchain identity authentication distribution dynamic key generation

Design and Implementation of Nonlinear Precoding for MIMO-SDMA Toward 6G Wireless

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China Communications 2024年第1期21卷 69-87页

作者： Chaowu wu Yue Xiao Shu Fang Gang wu National Key Laboratory of Wireless Communications University of Electronic Science and Technology of ChinaChengdu 611731China

In this paper,we present a novel and robust nonlinear precoding(NLP)design and detection structure specifically tailored for multiple-input multipleoutput space division multiple access(MIMO-SDMA)systems toward 6G *** approach aims to effectively mitigate the impact of imperfect channel estimation by leveraging the channel fluctuation mean square error(MSE)for reconstructing a highly accurate precoding matrix at the ***,we introduce a simplified receiver structure that eliminates the need for equalization,resulting in reduced interference and notable enhancements in overall system *** conduct both computer simulations and experimental tests to validate the efficacy of our proposed *** results reveals that the proposed NLP scheme offers significant performance improvements,making it particularly well-suited for the forthcoming 6G wireless.

关键词： MIMO-SDMA nonlinear precoding Tomlinson-Harashima precoding(THP) vector perturbation(VP)

Optically levitated micro gyroscopes with an MHz rotational vaterite rotor

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Microsystems & Nanoengineering 2024年第3期10卷 219-227页

作者： Kai Zeng Xiangming Xu Yulie wu Xuezhong wu Dingbang Xiao College of Intelligence Science and Technology National University of Defense TechnologyChangsha 410073China College of Information and Communication National University of Defense TechnologyWuhan 430000China Key Laboratory of Satellite Navigation Technology National University of Defense TechnologyChangsha 410073China

The field of levitated optomechanics has experienced significant advancements in manipulating the translational and rotational dynamics of optically levitated particles and exploring their sensing *** concept of using optically levitated particles as gyroscopes to measure angular motion has long been explored but has not yet been proven either theoretically or *** this study,we present the first rotor gyroscope based on optically levitated high-speed rotating *** gyroscope is composed of a micrometer-size ellipsoidal vaterite particle that is driven to rotate at MHz frequencies in a vacuum *** an external angular velocity is input,the optical axis deviates from its initial position,resulting in changes in the frequency and amplitude of the rotational *** analyzing these changes,the angular velocity of the input can be accurately detected,making it the smallest rotor gyroscope in the *** angular rate bias instability of the gyroscope is measured to be 0.08°/s and can be further improved to as low as 10^(−9)°/h theoretically by cooling the motion and increasing the angular moment of the levitated *** work opens a new application paradigm for levitated optomechanical systems and may pave the way for the development of quantum rotor gyroscopes.

关键词： particles rotational angular

Integrated Clustering and Routing Design and Triangle Path Optimization for UAV-Assisted Wireless Sensor Networks

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China Communications 2024年第4期21卷 178-192页

作者： Shao Liwei Qian Liping wu Mengru wu Yuan College of Information Engineering Zhejiang University of TechnologyHangzhou 310014China State Key Laboratory of Internet of Things for Smart City University of MacaoMacaoChina Department of Computer and Information Science University of MacaoMacaoChina

With the development of the Internet of Things(IoT),it requires better performance from wireless sensor networks(WSNs),such as larger coverage,longer lifetime,and lower ***,a large amount of data generated from monitoring and long-distance transmission places a heavy burden on sensor nodes with the limited battery *** this,we investigate an unmanned aerial vehicles assisted mobile wireless sensor network(UAV-assisted WSN)to prolong the network lifetime in this ***,we use UAVs to assist the WSN in collecting *** the current UAV-assisted WSN,the clustering and routing schemes are determined ***,such a separate consideration might not maximize the lifetime of the whole WSN due to the mutual coupling of clustering and *** efficiently prolong the lifetime of the WSN,we propose an integrated clustering and routing scheme that jointly optimizes the clustering and routing *** the whole network space,it is intractable to efficiently obtain the optimal integrated clustering and routing ***,we propose the Monte-Las search strategy based on Monte Carlo and Las Vegas ideas,which can generate the chain matrix to guide the algorithm to find the solution *** point-to-point collection leads to long collection paths,so a triangle optimization strategy is then proposed that finds a compromise path to shorten the collection path based on the geometric distribution and energy of sensor *** avoid the coverage hole caused by the death of sensor nodes,the deployment of mobile sensor nodes and the preventive mechanism design are *** emergency data transmission mechanism is further proposed to reduce the latency of collecting the latency-sensitive data due to the absence of *** with the existing schemes,the proposed scheme can prolong the lifetime of the UAVassisted WSN at least by 360%,and shorten the collection path of UAVs by 56.24%.

关键词： Monte-Las search strategy triangle path optimization unmanned aerial vehicles wireless sensor networks

Terminal-selective C（sp3）–H borylation of unbranched alkanes enabled by intermolecular radical sampling and LMCT photocatalysis

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National Science Review 2024年第5期11卷 96-98页

作者： Zhexuan Lei Jie wu Department of Chemistry National University of Singapore

The selective functionalization of C（sp3）–H bonds with subtle differences in alkanes is highly sought after due to its atom-and step-efficiency. The activation of C（sp3）–H bonds through hydrogen atom transfer （HAT） has been extensively exploited to produce a valueadded product from unfunctionalized material [1,2].

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TOFD检验技术在多跨连续钢箱梁工程中的应用

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河南科技 2015年第7X期34卷 80-83页

作者：李伟吴纪东郑州市市政工程总公司河南郑州450007

城市钢箱梁具有安装速度快、施工跨度相对较大的特点,然而钢箱梁往往是分段安装,其焊缝质量的好坏直接影响钢箱梁桥的安全度。常规的钢箱梁焊缝检验具有工期长、社会环境影响大的缺陷,本研究分别对钢箱梁桥焊缝采用TOFD技术和传统的焊... 详细信息

城市钢箱梁具有安装速度快、施工跨度相对较大的特点,然而钢箱梁往往是分段安装,其焊缝质量的好坏直接影响钢箱梁桥的安全度。常规的钢箱梁焊缝检验具有工期长、社会环境影响大的缺陷,本研究分别对钢箱梁桥焊缝采用TOFD技术和传统的焊缝检验技术进行检验,并对检验结果进行对比分析,为钢箱梁焊缝检验方法的选择提供了一定的参考。

关键词：钢箱梁焊缝 TOFD检验 RT拍片

BSIN: A Behavior Schema of Information Networks Based on Approximate Bisimulation

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Tsinghua Science and Technology 2024年第4期29卷 1092-1104页

作者： wujie Hu Jinzhao wu School of Electrical Engineering Guangxi UniversityNanning 530004China

Information networks are becoming increasingly important in practice. However, their escalating complexity is gradually impeding the efficiency of data mining. A novel network schema called the Behavior Schema of Information Networks (BSIN) is proposed to address this issue. This work defines the behavior of nodes as connected paths in BSIN, proposes a novel function distinguish behavior differences, and introduces approximate bisimulation into the acquisition of quotient sets for node types. The major highlight of BSIN is its ability to directly obtain a high-efficiency network on the basis of approximate bisimulation, rather than reducing the existing information network. It provides an effective representation of information networks, and the resulting novel network has a simple structure that more efficiently expresses semantic information than current network representations. The theoretical analysis of the connected paths between the original and the obtained networks demonstrates that errors are controllable;and semantic information is approximately retained. Case studies show that BSIN yields a simple network and is highly cost-effective.

关键词： data mining information network approximate bisimulation controllable error

Benzoyl cyanide, a general radical acylating reagent for photoredox-catalyzed benzylic site-selective acylation reactions

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Science China Chemistry 2024年第11期67卷 3833-3843页

作者： Zhaodong Zhu Jingjing wu Frontiers Science Center for Transformative Molecules Shanghai Key Laboratory for Molecular Engineering of Chiral Drugs School of Chemistry and Chemical Engineering Zhangjiang Institute for Advanced Study Shanghai Jiao Tong University

Based on rational design, benzoyl cyanide, a well-known ionic acylating reagent, has been developed as a general radical acylating reagent for benzylic site-selective acylation reactions for the first time. Using visible-light photoredox-catalyzed single electron transfer(SET) and hydrogen atom transfer(HAT) strategies, two different direct benzylic C–H acylation reactions with high atom economy have been developed. This newly developed radical acylating reagent could also be used to achieve three component acyltrifluoromethylation of styrenes, which is usually challenging to achieve by other means. All of these reactions proceed under mild nickel-free and NHC-free conditions with high functional group tolerance. In addition, based on our detailed mechanistic experiments, the process of radical-radical cross-coupling mechanism was suggested for these transformations.

关键词： photoredox catalysis benzylic C–H acylation radical acylating reagent HAT catalysis acyltrifluoromethylation