检索结果-南通市图书馆

Budget Allocation for Maximizing Viral Advertising in Social Networks

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2016年第4期31卷 759-775页

作者： Bo—LeiZhang Zhu-zhong Qian wen-zhong li Bin Tang Sang-Lu Lu Xiaoming Fu State Key Laboratory for Novel Software Technology Nanjing University Nanjing 210023 China Institute of Computer Science University of G5ttingen G5ttingen 37077 Germany

Viral advertising in social networks has arisen as one of the most promising ways to increase brand awareness and product sales. By distributing a limited budget, we can incentivize a set of users as initial adopters so that the advertising can start from the initial adopters and spread via sociM links to become viral. Despite extensive researches in how to target the most influential users, a key issue is often neglected： how to incentivize the initial adopters. In the problem of influence maximization, the assumption is that each user has a fixed cost for being initial adopters, while in practice, user decisions for accepting the budget to be initial adopters are often probabilistic rather than deterministic. In this paper, we study optimal budget allocation in social networks to maximize the spread of viral advertising. In particular, a concave probability model is introduced to characterize each user＇s utility for being an initial adopter. Under this model, we show that it is NP-hard to find an optimal budget allocation for maximizing the spread of viral advertising. We then present a novel discrete greedy algorithm with near optimal performance, and further propose scaling-up techniques to improve the time-efficiency of our algorithm. Extensive experiments on real-world social graphs are implemented to validate the effectiveness of our algorithm in practice. The results show that our algorithm can outperform other intuitive heuristics significantly in almost all cases.

关键词： social network influence maximization information diffusion submodular optimization

Joint multiple parameters estimation for coherent chirp signals using vector sensor array

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science in China(Series F) 2008年第1期51卷 93-100页

作者： wen zhong li liPing CHEN TianQi ZHANG XiXiang School of Electronic Engineering University of Electronic Science and Technology of China Chengdu 610054 China

In this paper, an algorithm is proposed to estimate starting frequency （SF）, chirp rate （CR）, 2-D direction-of-arrivals （DOA） and polarization of coherent chirp signals with vector sensor arrays. The fractional Fourier transformation （FRFT） is used to estimate SF and CR of chirp signals in this method. And a new correlation matrix is reconstructed to suppress the noise. The property of the vector sensor array is employed to solve the problem of insufficient rank from signal coherence. The L-shaped uniform array of expend aperture is used to improve the precision of es- timation, and the method of solving the ambiguity of angle under the condition of coherent signals is presented. The performance of this algorithm is compared with that of spatial smoothing method to verify the efficacy of this approach.

关键词： vector sensor array FRFT coherence

Next POI Recommendation Based on Location Interest Mining with Recurrent Neural Networks

在线全文

学校读者我要写书评

暂无评论

Journal of Computer Science & Technology 2020年第3期35卷 603-616页

作者： Ming Chen wen-zhong li lin Qian Sang-Lu Lu Dao-Xu Chen State Key Laboratory for Novel Software Technology Nanjing UniversityNanjing 210023China Sino-German Institutes of Social Computing Nanjing UniversityNanjing 210023China State Grid Electric Power Research Institute NARI Group CorporationNanjing 211000China

In mobile social networks,next point-of-interest(POI)recommendation is a very important function that can provide personalized location-based services for mobile *** this paper,we propose a recurrent neural network(RNN)-based next POI recommendation approach that considers both the location interests of similar users and contextual information(such as time,current location,and friends’preferences).We develop a spatial-temporal topic model to describe users’location interest,based on which we form comprehensive feature representations of user interests and contextual *** propose a supervised RNN learning prediction model for next POI *** based on real-world dataset verify the accuracy and efficiency of the proposed approach,and achieve best F1-score of 0.196754 on the Gowalla dataset and 0.354592 on the Brightkite dataset.

关键词： location interest location-based service point-of-interest(POI)recommendation mobile social network

Fabrication of Two-dimensional Monolayer and One-dimensional Wire of Zn-tetra-[3,5-di-t-butylphenyl]-porphyrin on Cu(100) Surface

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2006年第8期25卷 992-996页

作者： QIAN li-Ping WANG Xian XU Di WANG Zhou-Feng JIANG zhong-Jie DENG wen-li College of Materials Science and Engineering South China University of Technology Guangzhou 510640 China

We describe in this paper the fabrication of two- and one-dimensional nanostructures with organic molecular beam epitaxy （OMBE） principle based on controlled selfassembly by using adsorbate-substrate and intennolecular interactions that are important in molecular fabrication. Cu（100） single crystal was used as substrate in fabricating molecular nanostructures. Scanning tunneling microscopy （STM） experiments confirmed that Zn-tetra- [3,5-di-t-butylphenyl]porphyrin-molecules can be used to fabricate both monolayer and molecular wire on Cu（100） surface simultaneously, and the latter is arranged on the terrace edges. We herein briefly discuss the selectivity in terms of a mechanism in which the highest occupied and lowest unoccupied molecular orbitals （HOMO and LUMO） of the molecules interact with the surface.

关键词： fabrication two-dimensional monolayer one-dimensional molecular wire Zn-tetra-[3,5-di-t-butylphenyl]porphyrin

SEI/dead li-turning capacity loss for high-performance anode-free solid-state lithium batteries

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2024年第9期96卷 145-152页

作者： Qianwen Yin Tianyu li Hongzhang Zhang Guiming zhong Xiaofei Yang Xianfeng li Division of Energy Storage Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina University of Chinese Academy of Sciences Beijing 100049China Key Laboratory of Long-Duration and Large-Scale Energy Storage Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina Laboratory of Advanced Spectro-Electrochemistry and lithium-Ion Batteries Dalian National Laboratory for Clean EnergyDalian Institute of Chemical PhysicsChinese Academy of SciencesDalian 116023LiaoningChina

Anode-free solid-state lithium metal batteries(AF-SSLBs)have the potential to deliver higher energy density and improved safety beyond lithium-metal ***,the unclear mechanism for the fast capacity decay in AF-SSLBs,either determined by dead li or solid electrolyte interface(SEI),limits the proposal of effective strategies to prolong cycling *** clarify the underlying mechanism,herein,the evolution of SEI and dead li is quantitatively analyzed by a solid-state nuclear magnetic resonance(ss-NMR)technology in a typical liPF6-based polymer *** results show that the initial capacity loss is attributed to the formation of SEI,while the dead li dominates the following capacity loss and the growth rate is 0.141 mA h cm^(−2)cycle−*** reduce the active li loss,the combination of inorganic-rich SEI and self-healing electrostatic shield effect is proposed to improve the reversibility of li deposition/dissolution behavior,which reduces the capacity loss rate for the initial SEI and following dead li generation by 2.3 and 20.1 folds,*** a result,the initial Coulombic efficiency(ICE)and stable CE increase by 15.1%and 15.3%in li-Cu cells,which guides the rational design of high-performance AF-SSLBs.

关键词： Solid-state lithium batteries Solid-state NMR Anode-free SEI Dead li

Outpatient Surgery in zhongshan Ophthalmic Center： Promise and Problems

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2017年第13期130卷 1623-1624页

作者： Zhi-Gang Fan Dan-Dan Zhang zhong-wen li Yao Yang Xiao-Feng lin State Key Laboratory of Ophthalmology Zhongshan Ophthalmic Center Sun Yat-sen University Guangzhou Guangdong 510060 China

To the Editor： The Chinese government is actively advocating medical reform, aiming at reducing medical costs, and improving service quality. As to ophthalmology, transition from traditional hospitalized surgery to a predominant outpatient mode could be a solution. zhongshan Ophthalmic Center （ZOC） is one of the largest and leading ophthalmic centers in China,

关键词： Outpatient Surgery zhongshan Ophthalmic Center Promise and Problems

MPI/OpenMP-Based Parallel Solver for Imprint Forming Simulation

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2024年第7期140卷 461-483页

作者： Yang li Jiangping Xu Yun liu wen zhong Fei Wang School of Mechanical Engineering Jiangsu UniversityZhenjiang212016China School of Mechanical Engineering Wuhan Polytechnic UniversityWuhan430023China Shenyang Mint Company limited Shenyang110092China

In this research,we present the pure open multi-processing(OpenMP),pure message passing interface(MPI),and hybrid MPI/OpenMP parallel solvers within the dynamic explicit central difference algorithm for the coining process to address the challenge of capturing fine relief features of approximately 50 *** such precision demands the utilization of at least 7 million tetrahedron elements,surpassing the capabilities of traditional serial programs previously *** mitigate data races when calculating internal forces,intermediate arrays are introduced within the OpenMP *** helps ensure proper synchronization and avoid conflicts during parallel ***,in the MPI implementation,the coins are partitioned into the desired number of *** division allows for efficient distribution of computational tasks across multiple *** simulation examples are conducted to compare the three solvers with serial programs,evaluating correctness,acceleration ratio,and parallel *** results reveal a relative error of approximately 0.3%in forming force among the parallel and serial solvers,while the predicted insufficient material zones align with experimental ***,speedup ratio and parallel efficiency are assessed for the coining process *** pureMPI parallel solver achieves a maximum acceleration of 9.5 on a single computer(utilizing 12 cores)and the hybrid solver exhibits a speedup ratio of 136 in a cluster(using 6 compute nodes and 12 cores per compute node),showing the strong scalability of the hybrid MPI/OpenMP programming *** approach effectively meets the simulation requirements for commemorative coins with intricate relief patterns.

关键词： Hybrid MPI/OpenMP parallel computing MPI OpenMP imprint forming

Layered niobium carbide enabling excellent kinetics and cycling stability of li-Mg-B-H hydrogen storage material Layered niobium carbide enabling excellent kinetics

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Rare Metals 2024年第3期43卷 1153-1166页

作者： li-wen Lu Hui Luo Guang-Xu li Yun li Xin-Hua Wang Cun-Ke Huang Zhi-QiangLan wen-Zheng Zhou Jin Guo Mohammad Ismail Hai-Zhen liu Guangxi Novel Battery Materials Research Center of Engineering Technology Guangxi Colleges and Universities Key Laboratory of Blue Energy and Systems IntegrationSchool of Physical Science and TechnologyGuangxi UniversityNanning530004China State Key Laboratory of Featured Metal Materials and life-Cycle Safety for Composite Structures Nanning530004China School of Mechanical and Electrical Engineering Quzhou College of TechnologyQuzhou324000China Department of Materials Science and Engineering Zhejiang UniversityHangzhou310027China Faculty of Ocean Engineering Technology and Informatics Universiti Malaysia Terengganu21030Kuala NerusTerengganuMalaysia Key Laboratory of Advanced Energy Materials Chemistry(Ministry of Education) Nankai UniversityTianjin300071China

The li-Mg-B-H composite(2liBH_(4)+MgH_(2))has a high capacity of 11.4 wt%as a hydrogen storage ***,the slow kinetics and poor cycling stability severely restrict its practical *** this work,a layered Nb_(2)C MXene was first synthesized and then introduced to tailor the kinetics and cycling stability of the li-Mg-B-H *** milled 2liH+MgB_(2)composites were initially hydrogenated to obtain the 2liBH_(4)+MgH_(2)*** 2liBH_(4)+MgH_(2)+5wt%Nb_(2)C can release 9.0 wt%H_(2)in 30 min at 400℃,while it is only 2.7 wt%for the undoped 2liBH_(4)+MgH_(2).The dehydrogenation activation energies of MgH_(2)and liBH_(4)are 123 and 154 kJ·mol^(-1)respectively for the 5 wt%Nb_(2)C-doped composite,lower than the undoped composite(164 and 165 kJ·mol^(-1)).The 2liBH_(4)+MgH_(2)+5 wt%Nb_(2)C possesses excellent cycling stability,with the reversible capacity only slightly reduced from 9.4 wt%for the 1st cycle to 9.3 wt%for the 20th ***_(2)C keeps stable in the composite and acts as an efficient catalyst for the li-Mg-B-H *** is believed that both the layered structure and the active Nb element contribu te to the enhanced hydrogen storage performances of the li-Mg-B-H *** work confirms that the Nb_(2)C MXene with layered stru cture has a significant enhancing impact on the li-Mg-B-H hydrogen storage materials,which is different from the bulk NbC.

关键词： Hydrogen storage lithium borohydride Magnesium hydride Nb_(2)C MXene

Construction of core@double-shell structured energetic composites with simultaneously enhanced thermal stability and safety performance

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第4期34卷 134-142页

作者： Peng Wang wen Qian Ruolei zhong Fangfang He Xin li Jie Chen li Meng Yinshuang Sun Guansong He Institute of Chemical Materials China Academy of Engineering PhysicsMianyang 621900China State Key Laboratory of Environment-friendly Energy Materials School of Materials and ChemistrySouthwest University of Science and TechnologyMianyang 621010China

The poor thermal stability and high sensitivity severely hinder the practical application of hexanitrohexaazaisowurtzitane(CL-20).Herein,a kind of novel core@double-shell CL-20 based energetic composites were fabricated to address the above *** coordination complexes which consist of natural polyphenol tannic acid(TA) and Fe~Ⅲ were chosen to construct the inner shell,while the graphene sheets were used to build the outer *** resulting CL-20/TA-Fe~Ⅲ/graphene composites exhibited simultaneously improved thermal stability and safety performance with only 1 wt% double-shell content,which should be ascribed to the intense physical encapsulation effect from inner shell combined with the desensitization effect of carbon nano-materials from outer *** phase transition(ε to γ) temperature increased from 173.70 ℃ of pure CL-20 to 191.87℃ of CL-20/TA-Fe~Ⅲ/graphene ***,the characteristic drop height(H_(50)) dramatically increased from 14.7 cm of pure CL-20 to112.8 cm of CL-20/TA-Fe~Ⅲ/graphene composites,indicating much superior safety performance after the construction of the double-shell *** general,this work has provided an effective and versatile strategy to conquer the thermal stability and safety issues of CL-20 and contributes to the future application of high energy density energetic materials.

关键词： CL-20 Double-shell structure Thermal stability Safety performance Tannic acid Graphene sheets