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Beamforming design for covert broadcast communication with hidden adversary

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Science China(Information Sciences) 2024年第6期67卷 384-398页

作者： Weiyu CHEN Haiyang DING Shilian WANG Junshan LUO Fengkui GONG College of Electronic Science and technology National University of Defense Technology College of Information and Communication National University of Defense Technology state Key Laboratory of Integrated Service Networks Xidian University

This paper explores covert broadcast communication in a challenging situation in which the transmitter, Alice, faces uncertainty regarding the position of the passive adversary, Willie. In this situation,controlling the signal exposure becomes difficult. Specifically, this paper focuses on the cases where Alice can delimit the suspicious areas where Willie may be located. The suspicious areas can have arbitrary number and shapes. Under the Rician fading model, the analytical expression of Willie's detection performance is derived. Then, the transmit power, the beamforming direction, and the number of channel uses are jointly designed to minimize the optimal Willie's detection performance among all the possible positions of Willie, on the premise of satisfying receivers' quality-of-service requirements. To tackle the formulated knotty problem with an infinite number of irregular and discontinuous Willie's possible positions, the continuous nature of the antenna pattern is exploited to convert the original problem into the one with a finite number of possible positions, by sampling the suspicious areas. Then, different algorithms are developed to address the resultant non-convex optimization problem for single-antenna Willie and multi-antenna Willie, respectively. Numerical results demonstrate significant performance gains of the proposed scheme over the widely-adopted maximum ratio transmission scheme, which indicates that simply adjusting the main lobe towards the receiver is indeed far away from optimum and shows the importance of leveraging Alice's limited knowledge of Willie's position.

关键词： low-probability-of-detection communication multiple antennas covertness performance uncertain position parameters optimization

Microstructure Regulation and Combustion Performance Optimization of PVDF/Al Composite Powder by Non-covalent Functionalized Graphenes

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Journal of Wuhan university of technology(Materials Science) 2024年第4期39卷 904-911页

作者：易卓然 DENG Haoyuan QIN Mei 孙一 LUO Guoqiang state Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

Graphene prepared by non-covalent modification of sulfonated poly(ether-ether-ketone)(SPG)was combined with polyvinylidene fluoride(PVDF)/Al to improve the PVDF/Al thermal conductivity while reducing the effect of the thermal resistance at the graphene-polymer *** regulation rule of SPG with different contents on the energy release of fluorine-containing system was *** the content of SPG is 4%,the peak pressure and rise rate of SPG/PVDF/Al composite powder during ignition reach the maximum of 4845.28 kPa and 8683.58 kPa/*** the content of SPG is 5%,the PVDF/Al composite powder is completely coated by SPG,and the calorific value of the material reachs the maximum of 29.094 kJ/*** the design and micro-control of the composite powder,the calorific value of the material can be effectively improved,but the improvement of the mass release rate still depends on the graphene content and surface modification state.

关键词： energetic materials PVDF/Al composites graphene modification energy release combustion

A novel integrated microfluidic chip for on-demand electrostatic droplet charging and sorting

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Bio-Design and Manufacturing 2024年第1期7卷 31-42页

作者： Jinhui Yao Chunhua He Jianxin Wang Canfeng Yang Ye Jiang Zhiyong Liu Guanglan Liao Tielin Shi state Key Laboratory of Intelligent Manufacturing Equipment and technology Huazhong University of Science and TechnologyWuhan 430074China

On-demand droplet sorting is extensively applied for the efficient manipulation and genome-wide analysis of individual ***,state-of-the-art microfluidic chips for droplet sorting still suffer from low sorting speeds,sample loss,and labor-intensive preparation ***,we demonstrate the development of a novel microfluidic chip that integrates droplet generation,on-demand electrostatic droplet charging,and high-throughput *** charging electrode is a copper wire buried above the nozzle of the microchannel,and the deflecting electrode is the phosphate buffered saline in the microchannel,which greatly simplifies the structure and fabrication process of the ***,this chip is capable of high-frequency droplet generation and sorting,with a frequency of 11.757 kHz in the drop *** chip completes the selective charging process via electrostatic induction during droplet ***-demand charged microdroplets can arbitrarilymove to specific exit channels in a three-dimensional(3D)-deflected electric field,which can be controlled according to user requirements,and the flux of droplet deflection is thereby significantly ***,a lossless modification strategy is presented to improve the accuracy of droplet deflection or harvest rate from 97.49% to 99.38% by monitoring the frequency of droplet generation in real time and feeding it back to the charging *** chip has great potential for quantitative processing and analysis of single cells for elucidating cell-to-cell variations.

关键词： Copper wire Droplet generation Droplet sorting Microfluidic chips On-demand charging

Effect of Molecular Weight on Thermoelectric Performance of P3HT Analogues with 2-Propoxyethyl Side Chains

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Journal of Wuhan university of technology(Materials Science) 2024年第2期39卷 268-281页

作者：董得福 WANG Wei ZHAN Chun LI Chenglong ZHOU Qisheng 肖生强 state Key Laboratory of Advanced technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

By replacing hexyl chains in poly(3-hexylthiophene)(P3HT)with 2-propoxyethyls,four poly(3-(2-propoxyethyl)thiophene)(P3POET)homopolymers with comparable polydispersity indexes(PDI)and regioregularities were prepared herein in addition with step increment of about 7 kDa on numberaverage molecular weight(M_(n))from around 11 to 32 kDa(accordingly denoted as P11k,P18k,P25k,and P32k).When doped in film by FeCl_(3)at the optimized conditions,the maximum power factor(PF_(max))increases greatly from 4.3μW·m^(-1)·K^(-2)for P11k to 8.8μW·m^(-1)·K^(-2)for P18k,and further to 9.7μW·m^(-1)·K^(-2)for P25k,followed by a slight decrease to 9.2μW·m^(-1)·K^(-2)for *** close Seebeck coefficients(S)at PF_(max)are observed in these doped polymer films due to their consistent frontier orbital energy levels and Fermi *** main contribution to this PF_(max)evolution thus comes from the corresponding conductivities(σ).Theσvariation of the doped films can be rationally correlated with their microstructure evolution.

关键词： conjugated polymer molecular weight microstructure thermoelectric performance

Physics-informed deep Koopman operator for Lagrangian dynamic systems

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Science China(Information Sciences) 2024年第9期67卷 146-163页

作者： Xuefeng WANG Yang CAO Shaofeng CHEN Yu KANG Department of Automation University of Science and Technology of China state Key Laboratory of Fire Science University of Science and Technology of China Institute of Advanced technology University of Science and Technology of China

Accurate mechanical system models are crucial for safe and stable control. Unlike linear systems,Lagrangian systems are highly nonlinear and difficult to optimize because of their unknown system *** research thus used deep neural networks to generate linear models of original systems by mapping nonlinear dynamic systems into a linear space with a Koopman observable function encoder. The controller then relies on the Koopman linear model. However, without physical information constraints, ensuring control consistency between the original nonlinear system and the Koopman system is tough, as the learning process of the Koopman observation function is unsupervised. This paper thus proposes a two-stage learning algorithm that uses structural subnetworks to build a physics-informed network topology to simultaneously learn the Koopman observable functions and the system energy representation. In the Koopman matrix learning session, a quadratic-constrained optimization problem is solved to ensure that the Koopman representation satisfies the energy difference matching hard constraint. The proposed energy-preserving deep Lagrangian Koopman(EPDLK) framework effectively represents the dynamics of the Lagrangian system while ensuring control consistency. The effectiveness of EPDLK is compared with those of various Koopman observable function construction methods in multistep prediction and trajectory tracking tasks. EPDLK achieves better control consistency by guaranteeing energy difference matching, which facilitates the application of the control law generated on the Koopman system directly to the original nonlinear Lagrangian system.

关键词： Koopman operator Lagrangian physics-informed nonlinear model predictive control (MPC)

A hybrid WUDT-NAFnet for simultaneous source data deblending

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Petroleum Science 2024年第3期21卷 1649-1659页

作者： Chao-Fan Ke Shao-Huan Zu Jun-Xing Cao Xu-Dong Jiang Chao Li Xing-Ye Liu Key Laboratory of Earth Exploration and Information technology of Ministry of Education Chengdu University of Technology state Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of Technology College of Geophysics Chengdu University of Technology

Simultaneous source technology,which reduces seismic survey time and improves the quality of seismic data by firing more than one source with a narrow time interval,is compromised by the massive blended ***,deblending algorithms have been developed to separate this ***,deep learning(DL)has been proved its great potential in suppressing the *** most popular DL method employs neural network as a filter to attenuate the blended noise in an iterative estimation and subtraction framework(IESF).However,there are still amplitude distortion and blended noise residual problems,especially when dealing with weak signal submerged in strong *** address these problems,we propose a hybrid WUDT-NAFnet,which contains two *** first network is a wavelet based U-shape deblending transformer network(WUDTnet),incorporated into IESF as a robust regularization term to iteratively separate the blended *** second network is a nonlinear activate free network(NAFnet)designed to recover the event amplitude and further suppress the weak noise residual in *** the hybrid network,the blended noise can be separated purposefully and *** using synthetic and field seismic data demonstrate that the WUDTNAFnet outperforms traditional curvelet transform(CT)based method and the deblending transformer(DT)model in terms of ***,for field applications,the data augmentation method of bicubic interpolation is applied to mitigate the feature difference between synthetic and field ***,the trained network exhibits strong signal preservation ability in numerical field example without requiring additional training.

关键词： Simultaneous-source Deblending Deep learning Transformer

Flexible, thermal processable, self-healing, and fully bio-based starch plastics by constructing dynamic imine network

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Green Energy & Environment 2024年第10期9卷 1610-1618页

作者： Xiaoqian Zhang Haishan Zhang Guowen Zhou Zhiping Su Xiaohui Wang state Key Laboratory of Pulp and Paper Engineering South China University of Technology

The serious environmental threat caused by petroleum-based plastics has spurred more researches in developing substitutes from renewable *** is desirable for fabricating bioplastic due to its abundance and renewable ***,limitations such as brittleness,hydrophilicity,and thermal properties restrict its widespread *** overcome these issues,covalent adaptable network was constructed to fabricate a fully bio-based starch plastic with multiple advantages via Schiff base *** strategy endowed starch plastic with excellent thermal processability,as evidenced by a low glass transition temperature （Tg=20.15℃）.Through introducing Priamine with long carbon chains,the starch plastic demonstrated superior flexibility （elongation at break=45.2%） and waterproof capability （water contact angle=109.2°）.Besides,it possessed a good thermal stability and self-adaptability,as well as solvent resistance and chemical *** work provides a promising method to fabricate fully bio-based plastics as alternative to petroleum-based plastics.

关键词： Bioplastic Covalent adaptable networks Schiff base chemistry Thermal processability Self-healing

When debugging encounters artificial intelligence: state of the art and open challenges

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Science China(Information Sciences) 2024年第4期67卷 42-84页

作者： Yi SONG Xiaoyuan XIE Baowen XU School of Computer Science Wuhan University state Key Laboratory of Novel Software technology Nanjing University

Both software debugging and artificial intelligence techniques are hot topics in the current field of software engineering. Debugging techniques, which comprise fault localization and program repair, are an important part of the software development lifecycle for ensuring the quality of software systems. As the scale and complexity of software systems grow, developers intend to improve the effectiveness and efficiency of software debugging via artificial intelligence(artificial intelligence for software debugging, AI4SD). On the other hand, many artificial intelligence models are being integrated into safety-critical areas such as autonomous driving, image recognition, and audio processing, where software debugging is highly necessary and urgent(software debugging for artificial intelligence, SD4AI). An AI-enhanced debugging technique could assist in debugging AI systems more effectively, and a more robust and reliable AI approach could further guarantee and support debugging techniques. Therefore, it is important to take AI4SD and SD4AI into consideration comprehensively. In this paper, we want to show readers the path, the trend, and the potential that these two directions interact with each other. We select and review a total of 165 papers in AI4SD and SD4AI for answering three research questions, and further analyze opportunities and challenges as well as suggest future directions of this cross-cutting area.

关键词： software debugging fault localization program repair artificial intelligence machine learning

Adaptive sampling for corrugated plate digitization using a laser displacement sensor

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Science China(Technological Sciences) 2024年第5期67卷 1510-1523页

作者： WU ChengXing QI Qi CHEN BaiJin YANG JiXiang DING Han state Key Laboratory of Intelligent Manufacturing Equipment and technology School of Mechanical Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China state Key Laboratory of Intelligent Manufacturing Equipment and technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan430074China

The surface quality of a corrugated plate directly determines the heat transfer property of the thermal power mechanical *** detection methods are impractical for real-world production,being slow and *** contrast,the point laser displacement sensor,employing the optical triangle method,emerges as a promising device for assessing parts with variable curvature and highly reflective *** its benefits,high-density sampling by an innate frequency introduces challenges such as data redundancy and a poor signal-to-noise ratio,potentially affecting the efficiency and precision of subsequent data *** address these challenges,adjustable frequency data sampling has been developed for this sensor,allowing adaptive sampling for corrugated plate *** process begins with surface digitization to extract discrete points,which are transformed into intersection curves using the B-spline fitting ***,dominant points are identified,considering multigeometric constraints for curvature and arch ***,the sampling signal is adjusted based on the distribution information of dominant *** results indicate that the proposed method effectively minimizes redundant sampling without compromising the accurate capture of essential geometric features.

关键词： corrugated plate laser displacement sensor adaptive sampling dominant point curvature arch height