查看更多>>摘要：In the era of intelligent economy,the click-through rate(CTR)prediction system can evaluate massive service information based on user historical information,and screen out the products that are most likely to be favored by users,thus realizing customized push of information and achieve the ultimate goal of improving economic benefits.Sequence modeling is one of the main research directions of CTR prediction models based on deep learning.The user's general interest hidden in the entire click history and the short-term interest hid-den in the recent click behaviors have different influences on the CTR prediction results,which are highly important.In terms of capturing the user's general interest,existing models paid more attention to the relationships between item embedding vectors(point-level),while ig-noring the relationships between elements in item embedding vectors(union-level).The Lambda layer-based Convolutional Sequence Em-bedding(LCSE)model proposed in this paper uses the Lambda layer to capture features from click history through weight distribution,and uses horizontal and vertical filters on this basis to learn the user's general preferences from union-level and point-level.In addition,we also incorporate the user's short-term preferences captured by the embedding-based convolutional model to further improve the prediction re-sults.The AUC(Area Under Curve)values of the LCSE model on the datasets Electronic,Movie & TV and MovieLens are 0.870 7,0.903 6 and 0.946 7,improving 0.45％,0.36％and 0.07％over the Caser model,proving the effectiveness of our proposed model.
查看更多>>摘要：Fog computing utilizes devices in the edge network to transmit data with very low latency and supports high mobility.How-ever,fog computing inherits security and privacy problems from cloud computing.Therefore,various privacy schemes for fog computing have been proposed to prevent different types of attacks.Recently,Weng et al proposed a fog computing authentication scheme;after ana-lyzing,we found that Weng et al's scheme cannot resist user tracking attack and user impersonation attack.Then,we propose an improved scheme through adding a password,modifying the calculation method of Ei,and adding timestamps.In addition,we also compare the im-proved scheme with existing authentication schemes in terms of security and computational efficiency.The results show that the improved scheme is more secure and has less computation.
查看更多>>摘要：In this paper,we propose a novel shear gradient operator by combining the shear and gradient operators.The shear gradient op-erator performs well to capture diverse directional information in the image gradient domain.Based on the shear gradient operator,we ex-tend the total variation(TV)norm to the shear total variation(STV)norm by adding two shear gradient terms.Subsequently,we introduce a shear total variation deblurring model.Experimental results are provided to validate the ability of the STV norm to capture the detailed in-formation.Leveraging the Block Circulant with Circulant Blocks(BCCB)structure of the shear gradient matrices,the alternating direction method of multipliers(ADMM)algorithm can be used to solve the proposed model efficiently.Numerous experiments are presented to verify the performance of our algorithm for non-blind image deblurring.
查看更多>>摘要：Ciphertext-policy attribute-based encryption(CP-ABE)is widely employed for secure data sharing and access control.How-ever,its dependence on a single authority introduces security and performance challenges.Despite the existence of multi-authority CP-ABE approaches,persistent issues such as single points of failure and high computation cost on the user side remain.This study proposes a novel solution named blockchain-based and decentralized attribute-based encryption(BDAE)for data sharing.BDAE enhances traditional scheme by integrating blockchain and distributed key generation technology.The scheme employs an(n,t)threshold secret sharing algo-rithm,coupled with the Pedersen verifiable secret sharing method,for attribute key generation.This combination ensures key credibility,facilitates joint attribute management,and addresses single bottleneck and key verification issues.Integrated into a blockchain system,the scheme utilizes smart contracts for fine-grained access control and outsourced computing.Blockchain's decentralization and access logs make data sharing tamper-resistant and auditable.Moreover,simulation comparisons demonstrate that the scheme effectively reduces de-cryption overhead on the user side,meeting practical application requirements.
查看更多>>摘要：For graphs G and H,an embedding of G into His an injection φ:V(G)→ V(H)such that φ(a)φ(b)∈ E(H)whenever ab ∈ E(G).A packing of p graphs G1,G2,…,Gp into His a p-tuple Φ=(φ1,φ2,…,φp)such that,for i=1,2,…,p,φi is an embedding of Gi into H and the p sets φi(E(Gi))are mutually disjoint.Motivated by the"Tree Packing Conjecture"made by Gy(a)rf(a)s and Lehel,Wang Hong conjectured that for each k-partite tree,there is a packing of two copies of T(X)into a complete k-partite graph Bn+m(Y),where m=(「)k/2」.In this paper,we confirm this conjecture for k=4.
查看更多>>摘要：This paper is concerned with radially positive solutions of the k-Hessian equation involving a Matukuma-type source Sk(D2(-φ))=|x|λ-2/(1+|x|2)λ/2φq,x∈Ω,where Sk(D2(-φ))is the k-Hessian operator,q＞k＞1,λ＞0,n＞2k,k ∈ N.and Ω is a suitable bounded do-main in Rn.It turns out that there are two different types of radially positive solutions for k＞1,i.e.,M-solution(singular at r=0)and E-solution(regular at r=0),which is distinct from the case when k=1.For 1＜q＜[(n-2+λ)k]/(n-2k),we apply an iterative approach to im-prove accuracy of asymptotic expansions of M-solution step by step to the desired extend.In contrast to the case k=1,we require a more precise range of parameters due to repeated application of Taylor expansions,which also makes asymptotic expansions need more delicate investigation.
查看更多>>摘要：In this paper,we consider the eigenvalue problem of the singular differential equation-△ui-h/|x|2ui+V(x)ui=λi(V,h)ui in a bounded open ball with Dirichlet boundary condition in 3-dimensional space,where,V ∈(V)={a ∈ L∞(Ω)|0≤a≤M a.e.,M is a given con-stant}.And we have made a detailed characterization of the weak solution space.Furthermore,the existence of the minimum eigenvalue and the fundamental gap are provided.
查看更多>>摘要：Time scale is a new and powerful tool for dealing with complex dynamics problems.The main result of this study is the exact invariants and adiabatic invariants of the generalized Birkhoffian system and the constrained Birkhoffian system on time scales.Firstly,we establish the differential equations of motion for the above two systems and give the corresponding Noether symmetries and exact invari-ants.Then,the perturbation to the Noether symmetries and the adiabatic invariants for the systems mentioned above under the action of slight disturbance are investigated,respectively.Finally,two examples are provided to show the practicality of the findings.
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