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Rare Metals 2024年第9期43卷 4367-4376页

作者： Wei Chen Ya-Hui Sun Tian Xu Xue-Bin Yu Guang-Lin Xia department of Materials science Fudan University

2LiBH4-MgH2composite is one of the most attractive reactive hydride composites with a theoretic hydrogen capacity of 10.8 wt%.However,the large nucleation restriction of MgB2during the second step of dehydrogenation results in sluggish hydrogen storage kinetics and high operating temperature,which hinders its practical application as on-board hydrogen storage ***,Al3Ti doped Al nanoparticles （AT NPs） are prepared by a facile chemical reduction reaction to improve the hydrogen storage performance of *** the initial H2desorption process,MgAlB4and TiB2that have identical crystal structure and low d-value mismatch with MgB2resulting from the reaction between AT NPs and 2LiBH4-MgH2composite serve as effective nucleation sites for the formation of *** a result,the apparent activation energy of the two-step H2desorption of AT NPs doped 2LiBH4-MgH2composite are notably decreased to （110.0±5.9） and（119.6±1.4） kJ·mol-1,which is 55.5 and 33.5 kJ·mol-1lower than that of the undoped *** importantly,a reversible hydrogen storage capacity of 9.2 wt%after 10cycles of H2desorption and adsorption could be achieved,corresponding to a capacity retention rate of 99%.The building of reactive bimetallic catalyst towards in situ formation of heterogeneous nucleation sites provides a new strategy for improving the hydrogen storage performance of reactive hydride composites.

关键词： Catalytic effects Heterogeneous nucleation Reactive hydride composites Reversible hydrogen storage

Berry-Esseen bounds for self-normalized sums of locally dependent random variables

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science China Mathematics 2024年第11期67卷 2629-2652页

作者： Zhuo-Song Zhang department of Statistics and Data science Southern University of Science and Technology

The Berry-Esseen bound provides an upper bound on the Kolmogorov distance between a random variable and the normal *** this paper,we establish Berry-Esseen bounds with optimal rates for self-normalized sums of locally dependent random variables,assuming only a second-moment *** proof leverages Stein's method and introduces a novel randomized concentration inequality,which may also be of independent interest for other *** main results have applied to self-normalized sums of m-dependent random variables and graph dependency models.

关键词： Berry-Esseen bounds self-normalized sums localdependence $m$-dependence graph dependency

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Improving Video Watermarking through Galois Field GF(2^(4)) Multiplication Tables with Diverse Irreducible Polynomials and Adaptive Techniques

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Computers, Materials & Continua 2024年第1期78卷 1423-1442页

作者： Yasmin Alaa Hassan Abdul Monem S.Rahma department of Computer science College of ScienceUniversity of BaghdadBaghdadIraq department of Computer science College of ScienceAl-Maarif University CollegeAl-AnbarIraq

Video watermarking plays a crucial role in protecting intellectual property rights and ensuring content *** study delves into the integration of Galois Field(GF)multiplication tables,especially GF(2^(4)),and their interaction with distinct irreducible *** primary aim is to enhance watermarking techniques for achieving imperceptibility,robustness,and efficient execution *** research employs scene selection and adaptive thresholding techniques to streamline the watermarking *** selection is used strategically to embed watermarks in the most vital frames of the video,while adaptive thresholding methods ensure that the watermarking process adheres to imperceptibility criteria,maintaining the video's visual ***,careful consideration is given to execution time,crucial in real-world scenarios,to balance efficiency and *** Peak Signal-to-Noise Ratio(PSNR)serves as a pivotal metric to gauge the watermark's imperceptibility and video *** study explores various irreducible polynomials,navigating the trade-offs between computational efficiency and watermark *** parallel,the study pays careful attention to the execution time,a paramount consideration in real-world scenarios,to strike a balance between efficiency and *** comprehensive analysis provides valuable insights into the interplay of GF multiplication tables,diverse irreducible polynomials,scene selection,adaptive thresholding,imperceptibility,and execution *** evaluation of the proposed algorithm's robustness was conducted using PSNR and NC metrics,and it was subjected to assessment under the impact of five distinct attack *** findings contribute to the development of watermarking strategies that balance imperceptibility,robustness,and processing efficiency,enhancing the field's practicality and effectiveness.

关键词： Video watermarking galois field irreducible polynomial multiplication table scene selection adaptive thresholding

Enhanced termination of zinc and cadmium ions from wastewater employing plain and chitosan-modified mxenes: synthesis, characterization,and adsorption performance

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Green Chemical Engineering 2024年第3期5卷 339-347页

作者： Njood R.Azeez Suhaib S.Salih Mohammed Kadhom Harith N.Mohammed Tushar K.Ghosh department of Chemical Engineering College of Engineering University of Tikrit department of Environmental science College of Energy and Environmental Science Al-Karkh University of Science department of Nuclear science & Engineering Institute University of Missouri-Columbia

Zinc and cadmium pollutants cause a significant environmental effect that cannot be ignored. Due to their considerable amount in an aqueous environment, industries are seeking suitable adsorbents that are environmentally friendly and inexpensive for removing metals from wastewater before disposing of them in surface waters. This research employed original MXene(MX) and chitosan-modified MXene(CSMX) to extract zinc(Zn(Ⅱ)) and cadmium(Cd(Ⅱ)) metal ions from water-based solutions. The composite material produced was analyzed using techniques such as X-ray Diffraction(XRD), Scanning Electron Microscopy(SEM), Fourier Transform Infrared Spectroscopy(FTIR), and Brunauer-Emmett-Teller(BET). The effects of contact duration, p H of the solution, and initial concentration of metal ions on the adsorption process of Zn(Ⅱ) and Cd(Ⅱ) onto both MX and CSMX composites were investigated. MX and prepared CSMX composite presented a high adsorption capacity for both studied heavy metals, which were 91.55 and 73.82 mg/g for Zn(Ⅱ) and Cd(Ⅱ) onto MX, 106.84 and 93.07 mg/g for Cd(Ⅱ) and Zn(Ⅱ) onto CSMX composite, respectively. Furthermore, the maximum competitive adsorption capacities for Zn(Ⅱ) onto MX and CSMX composites are 77.29 and 93.47 mg/g, and for are Cd(Ⅱ)60.30 and 79.66 mg/g, respectively. Hence, the removal capacities for both single and competitive metal ions were superior to CSMX composite. However, the adsorption capacities after five successive regeneration sequences were only dropped by 13.2% for Zn(Ⅱ) and 17.4% for Cd(Ⅱ) onto the CSMX composite compared to the first cycle. These results confirm that both metals could be efficiently terminated from wastewater, which makes the prepared CSMX composite a favorable candidate adsorbent in practical applications.

关键词： Adsorption Chitosan MXene Zn(II) Cd(II) Wastewater

Federated Learning Security and Privacy-Preserving Algorithm and Experiments Research Under Internet of Things Critical Infrastructure

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Tsinghua science and Technology 2024年第2期29卷 400-414页

作者： Nasir Ahmad Jalali Hongsong Chen department of Computer science University of Science and Technology Beijing(USTB)Beijing 100083China

The widespread use of the Internet of Things(IoTs)and the rapid development of artificial intelligence technologies have enabled applications to cross commercial and industrial band *** such systems,all participants related to commercial and industrial systems must communicate and generate ***,due to the small storage capacities of IoT devices,they are required to store and transfer the generated data to third-party entity called“cloud”,which creates one single point to store their ***,as the number of participants increases,the size of generated data also ***,such a centralized mechanism for data collection and exchange between participants is likely to face numerous challenges in terms of security,privacy,and *** address these challenges,Federated Learning(FL)has been proposed as a reasonable decentralizing approach,in which clients no longer need to transfer and store real data in the central ***,they only share updated training models that are trained over their private *** the same time,FL enables clients in distributed systems to share their machine learning models collaboratively without their training data,thus reducing data privacy and security ***,slow model training and the execution of additional unnecessary communication rounds may hinder FL applications from operating properly in a distributed ***,these unnecessary communication rounds make the system vulnerable to security and privacy issues,because irrelevant model updates are sent between clients and ***,in this work,we propose an algorithm for fully homomorphic encryption called Cheon-Kim-Kim-Song(CKKS)to encrypt model parameters for their local information privacy-preserving *** proposed solution uses the impetus term to speed up model convergence during the model training ***,it establishes a secure communication channel between IoT devices and the *** a

关键词： Federated Learning(FL) Internet of Things(IoTs) lightweight Transport Layer Security(iTLS) Cheon-Kim-Kim-Song(CKKS)

Skill enhancement learning with knowledge distillation

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science China(Information sciences) 2024年第8期67卷 206-220页

作者： Naijun LIU Fuchun SUN Bin FANG Huaping LIU department of Computer science and Technology Tsinghua University

Skill learning through reinforcement learning has significantly progressed in recent years. However, it often struggles to efficiently find optimal or near-optimal policies due to the inherent trial-and-error exploration in reinforcement learning. Although algorithms have been proposed to enhance skill learning efficacy, there is still much room for improvement in terms of skill learning performance and training stability. In this paper, we propose an algorithm called skill enhancement learning with knowledge distillation(SELKD), which integrates multiple actors and multiple critics for skill learning. SELKD employs knowledge distillation to establish a mutual learning mechanism among actors. To mitigate critic overestimation bias,we introduce a novel target value calculation method. We also perform theoretical analysis to ensure the convergence of SELKD. Finally, experiments are conducted on several continuous control tasks, illustrating the effectiveness of the proposed algorithm.

关键词： skill learning enhancement learning reinforcement learning knowledge distillation

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Topologically Correct Intersection Curves of Two Trimmed Quadrics with Tolerance Control

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Journal of Systems science & Complexity 2024年第5期37卷 2207-2239页

作者： SHAO Wenbing CHEN Falai department of Mathematics University of Science and Technology of China

Surface/surface intersection is a fundamental problem in Compute Aided Design and Geometric Modeling since it is essential to solid modeling, numerically controlled machining, feature recognition, computer animation, etc. In practical applications, quadric surfaces, which are the most basic type of surfaces, are typically bounded surfaces trimmed by a sequence of planes. In this paper,a robust algorithm is proposed for computing the intersection curve segments of two trimmed quadrics based on the parametric representation of the intersection curves of two quadrics. The proposed algorithm guarantees correct topology and ensures that the approximation errors of the end points of the intersection curve segments are less than a given tolerance. The error control is based on an effective solution to a set of polynomial inequality system using the root isolation technique. Some examples are presented to validate the robustness and effectiveness of the proposed algorithm.

关键词： Polynomial inequality system root isolation surface/surface intersection tolerance control trimmed quadrics

Categorizing methods for integrating machine learning with executable specifications

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science China(Information sciences) 2024年第1期67卷 5-19页

作者： David HAREL Raz YERUSHALMI Assaf MARRON Achiya ELYASAF department of Computer science and Applied Mathematics Weizmann Institute of Science department of Software and Information Systems Engineering Ben-Gurion University of the Negev

Deep learning(DL),which includes deep reinforcement learning(DRL),holds great promise for carrying out real-world tasks that human minds seem to cope with quite *** promise is already delivering extremely impressive results in a variety of ***,while DL-enabled systems achieve excellent performance,they are far from *** has been demonstrated,in several domains,that DL systems can err when they encounter cases they had not hitherto ***,the opacity of the produced agents makes it difficult to explain their behavior and ensure that they adhere to various requirements posed by human *** the other end of the software development spectrum of methods,behavioral programming(BP) facilitates orderly system development using self-standing executable modules aligned with how humans intuitively describe desired system *** this paper,we elaborate on different approaches for combining DRL with BP and,more generally,machine learning(ML) with executable specifications(ES).We begin by defining a framework for studying the various approaches,which can also be used to study new emerging approaches not covered *** then briefly review state-of-the-art approaches to integrating ML with ES,continue with a focus on DRL,and then present the merits of integrating ML with *** conclude with guidelines on how this categorization can be used in decision making in system development,and outline future research challenges.

关键词： machine learning artificial intelligence grey box learning domain knowledge rules behavioral programming deep reinforcement learning survey

Optoelectronic and thermoelectric properties of spinel chalcogenides HgLa2X4（X=S and Se）:A first-principles study

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Journal of Rare Earths 2024年第10期42卷 1927-1936页

作者： Aparna Dixit Inas A.Ahmed Jisha Annie Abraham Zeinhom M.El-Bahy Mumtaz Manzoor Sajad Ahmad Dar Ramesh Sharma department of Basic science and Humanities Pranveer Singh Institute of Technology department of Chemistry Faculty of ScienceKing Khalid University department of Physics National Defence Academy department of Chemistry Faculty of ScienceAl-Azhar University Institute of Physics Slovak Academy of Sciences department of Physics Motilal Vigyan Mahavidyalya College department of Applied science Feroze Gandhi Institute of Engineering and Technology

We investigated spinel chalcogenides HgLa2（S/Se）4by using density function theory,and scrutinized the structural,optical,electrical,mechanical and thermoelectric transport characteristics of HgLa2（S/Se）4spinel *** enthalpy of formation,energy of cohesion,and energy volume optimum plots were used to obtain the stability as well as the perfect ground state of these *** ductility of these materials was the best illustrated with the help of Poisson's and Pugh's *** band gap results were obtained using Trans and Blaha modified Becke-Johanson potential（TB-mBJ）.Both the materials present semi-conducting nature with direct band gap equal to 1.449 and 0.892 eV respectively for HgLa2S4and *** were also made for optical characteristics with the values of dielectric function,absorption coefficient,optical conductivity,reflectivity,and refractive *** to the findings,both of these materials are suitable for infrared optoelectronic *** materials were found to have promising optoelectronic and thermoelectric applications after their optical properties and transport aspects were *** tiny levels of temperature conductivities,substantial am ounts of power conductivities,the figure of merit（more than unity）,as well as Seebecs coefficients all point to the potential use of both the materials in thermoelectric power generators.

关键词： Density functional theory Direct band gap Optoelectronic Power factor Semiconductors Thermoelectric

What can we learn from quality assurance badges in open-source software?

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science China(Information sciences) 2024年第4期67卷 146-163页

作者： Feng LI Yiling LOU Xin TAN Zhenpeng CHEN Jinhao DONG Yang LI Xuanzhi WANG Dan HAO Lu ZHANG MoE Key Lab of HCST School of Computer SciencePeking University department of Computer science Purdue University School of Computer science & Engineering Beihang University(BUAA) department of Computer science University College London(UCL)

In the development of open-source software(OSS), many developers use badges to give an overview of the software and share some key features/metrics conveniently. Among various badges, quality assurance(QA) badges make up a large proportion and are the most prevalent because QA is of vital importance in software development, and ineffective QA may lead to anomalies or defects. In this paper, we focus on QA badges in open-source projects, which present quality assurance information directly and instantly,and aim to produce some interesting findings and provide practical implications. We collect and analyze 100000 projects written in popular programming languages from GitHub and conduct a comprehensive empirical study both inside and outside QA badges. Inside QA badges, we build a category classification for all QA badges based on the properties they focus on, which shows the types of QA badges developers use. Then,we analyze the frequency of the properties that QA badges focus on, and property combinations, too, which present their use status. We find that QA badges focus on various properties while developers give different preferences to different properties. The use status also differs between different programming languages. For example, projects written in C focus on Security to a great extent. Our findings also provide implications for developers and badge providers. Outside QA badges, we conduct a correlation analysis between QA badges and some software metrics that have potential relationships with code quality, contribution quality, and popularity. We find that QA badges have statistically significant correlations with various software metrics.

关键词： quality assurance badge open-source software code quality empirical study