Quantum-Resistant Multi-Feature Attribute-Based Proxy Re-Encryption Scheme for Cloud Services

Cloud-based services have powerful storage functions and can provide accurate computation.However,the question of how to guarantee cloud-based services access control and achieve data sharing security has always been a research highlight.Although the attribute-based proxy re-encryption(ABPRE)schemes based on number theory can solve this problem,it is still difficult to resist quantum attacks and have limited expression capabilities.To address these issues,we present a novel linear secret sharing schemes(LSSS)matrix-based ABPRE scheme with the fine-grained policy on the lattice in the research.Additionally,to detect the activities of illegal proxies,homomorphic signature(HS)technology is introduced to realize the verifiability of re-encryption.Moreover,the non-interactivity,unidirectionality,proxy transparency,multi-use,and anti-quantum attack characteristics of our system are all advantageous.Besides,it can efficiently prevent the loss of processing power brought on by repetitive authorisation and can enable precise and safe data sharing in the cloud.Furthermore,under the standard model,the proposed learning with errors(LWE)-based scheme was proven to be IND-sCPA secure.

A second-order convergent and linearized difference schemefor the initial-boundary value problemof the Korteweg-de Vries equation

To numerically solve the initial-boundary value problem of the Korteweg-de Vries equation,an equivalent coupled system of nonlinear equations is obtained by the method of reduction of order.Then,a difference scheme is constructed for the system.The new variable introduced can be separated from the difference scheme to obtain another difference scheme containing only the original variable.The energy method is applied to the theoretical analysis of the difference scheme.Results show that the difference scheme is uniquely solvable and satisfies the energy conservation law corresponding to the original problem.Moreover,the difference scheme converges when the step ratio satisfies a constraint condition,and the temporal and spatial convergence orders are both two.Numerical examples verify the convergence order and the invariant of the difference scheme.Furthermore,the step ratio constraint is unnecessary for the convergence of the difference scheme.Compared with a known two-level nonlinear difference scheme,the proposed difference scheme has more advantages in numerical calculation.

Alternating segment explicit-implicit scheme for nonlinear third-order KdV equation

A group of asymmetric difference schemes to approach the Korteweg-de Vries （KdV） equation is given here. According to such schemes, the full explicit difference scheme and the full implicit one, an alternating segment explicit-implicit difference scheme for solving the KdV equation is constructed. The scheme is linear unconditionally stable by the analysis of linearization procedure, and is used directly on the parallel computer. The numerical experiments show that the method has high accuracy.

NEW SECRET SHARING SCHEME BASED ON LINEAR CODE

A secret sharing system can be damaged when the dealer cheating occurs.In this paper,two kinds of secret sharing schemes based on linear code are proposed.One is a verifiable scheme which each participant can verify his own share from dealer's distribution and ensure each participant to receive valid share.Another does not have a trusted center,here,each participant plays a dual-role as the dealer and shadow(or share) provider in the whole scheme.

Nonstandard Numerical Schemes for a Linear Stochastic Oscillator with Additive Noise

In order to simulate a linear stochastic oscillator with additive noise,improved nonstandard optimal(INSOPT) schemes are derived utilizing the nonstandard finite difference(NSFD)technique and the improvement technique.These proposed schemes reproduce long time features of the oscillator solution exactly.Their abilities in preserving the symplecticity,the linear growth property of the second moment and the oscillation property of the solution of the stochastic oscillator system on long time interval are studied.It can be shown that the component { x_n}_(n≥1) of the INSOPT schemes switch signs infinitely many times as n →∞,almost surely.Further,the mean-square convergence order of 1 is obtained for these INSOPT schemes.Finally,numerical experiments illustrate intuitively the results obtained in this paper.

UNIFORM DIFFERENCE SCHEME FOR A SINGULARLY PERTURBED LINEAR 2ND ORDER HYPERBOLIC PROBLEM WITH ZEROTH ORDER REDUCED EQUATION

In this paper a singularly perturbed linear second order hyperbolic problem with zeroth order reduced equation is discussed. Firstly, an energy inequality of the solution and an estimate of the remainder term of the asymptotic solution are given. Then an exponentially fitted difference scheme is developed in an equidistant mesh. Finally, uniform convergence in small parameter is proved in the sense of discrete energy norm.

A HIGH ACCURACY DIFFERENCE SCHEME FOR THE SINGULAR PERTURBATION PROBLEM OF THE SECOND-ORDER LINEAR ORDINARY DIFFERENTIAL EQUATION IN CONSERVATION FORM

In this paper, combining the idea of difference method and finite element method, we construct a difference scheme for a self-adjoint problem in conservation form. Its solution uniformly converges to that of the original differential equation problem with order h3.

基于有限域上奇异线性空间的(m+1,1)型子空间的结合方案的构造

基于有限域上的奇异线性空间,定义X为所有包含一个固定的(m-1,0)型的子空间的(m+1,1)型子空间组成的集合,根据X中任意两个子空间的和的不同类型,构造了一个X上类数为5的结合方案.此外,给出了该结合方案的所有交叉数.

Rosenau-KdV-RLW方程的高精度线性化差分格式

利用有限差分方法研究一类非线性Rosenau-KdV-RLW方程的数值解,为进一步提高差分格式的理论精度,在时间层和空间层分别进行外推离散,构造一种新的高精度三层外推线性化差分格式。数值实验证明该差分方案是有效的,且空间层的理论精度达到四阶。

联盟链下的高效车联网数据安全共享研究

[目的/意义]旨在解决现有的车联网数据共享方案中计算开销大、共享效率低、安全性不足等问题。[方法/过程]设计了一个车联网高效数据安全共享方案,采用基于线性秘密共享(LSSS)的密文策略属性加密(CP-ABE)算法和基于联盟区块链群组技术,实现了车联网高效数据共享,减少数据冗余,并通过共识机制的优化,进一步提高时间效率,同时确保车辆实体的数据安全性和隐私性。[结果/结论]该方案能够适应车联网快速移动、动态变化的复杂特性,可实现灵活访问控制和高自由度的数据共享,满足车联网场景需求。

牂牁江大桥成桥线形施工误差及控制方案分析

文中以牂牁江大桥悬索桥施工项目为例,系统分析了主梁施工初始偏差、主缆施工初始偏差、主梁结构自重及弹性模量偏差、吊索预应力张拉偏差等因素对成桥线形的影响,并提出针对性控制方案。相关研究成果可为同类悬索桥成桥线形施工控制提供参考。

车联网中支持直接撤销的外包属性签名方案

数字签名在应对车联网中数据窜改威胁时扮演着重要作用,然而现有的签名方案在灵活性、效率、隐私保护、用户密钥管理等方面存在诸多问题,难以在车联网中释放其潜力。针对这些问题,提出了一个面向车联网的直接可撤销外包属性签名方案。该方案使用了基于线性秘密分享的签名策略机制,赋予车联网用户在签名生成和验证方面的灵活性和隐私保护。此外,设计了一种高效的用户密钥直接撤销机制,以提供对用户的实时撤权。所提方案还构造了一种外包验证方法,从而显著降低了验证者的计算和存储开销。安全性分析结果表明,所提方案在选择消息攻击下具有不可伪造性,并且能够抵抗合谋攻击。实验结果表明了该方案相较于其他方案的优势及其在车联网中的实用性。

轨道交通线路规划与设计研究

轨道交通作为城市公共交通的重要组成部分,在其建设过程中应从城市空间布局、功能定位、客流需求及发展趋势等方面综合考虑,充分发挥轨道交通在城市中的骨干作用。从轨道交通线路规划与设计的角度,对线路选线、线形方案比选、跨座式单轨等关键技术问题开展研究,并在此基础上提出了相关的建议。研究成果可为轨道交通规划设计提供参考,对我国城市轨道交通规划和建设具有积极的指导作用。

医疗云平台中个人健康档案转诊时的安全共享方案

为解决医疗云平台共享个人健康档案(personal health record,PHR)存在的隐私泄露和加解密效率不理想的问题,以医疗云平台中帕金森病患者的转诊场景为例,提出了一种基于线性秘密共享的改进密文属性代理重加密方案(improved linear secret sharing based ciphertext attribute proxy re-encryption scheme,LCPS)。该方案利用线性秘密共享技术来隐藏访问策略中的隐私属性,降低因访问策略暴露引发的隐私泄露风险;该方案还对代理重加密算法进行改进,通过减少复杂的双线性运算,提高了加解密效率。结果表明,LCPS在加解密方面的表现要优于其他方案。在判定性q-BDHE(q-decisional bilinear Diffie-Hellman exponent)困难假设下具有选择明文攻击时的不可区分性(indistinguishability under chosen-plaintext attack,IND-CPA)。该方案具有可移植性,同样适用于医疗云中其他病症转诊时的个人健康档案安全共享。

BBM-Burgers方程的非协调有限元方法的超收敛分析

研究Benjamin-Bona-Mahony-Burgers(BBM-Burgers)方程的非协调EQ_(1)^(rot)元的线性化BDF格式下的超收敛性质。通过使用数学归纳法来处理非线性项,并利用该单元已有的高精度结果及插值后处理技术,得到了在对空间剖分尺度和时间步长无网格比约束的前提下,关于离散H^(1)-模意义下具有O(h^(2)+τ^(2))阶的超逼近和超收敛结果。最后,通过给出数值算例验证了理论分析的正确性。

拱桥斜拉扣挂系统高效拆除技术研究

针对大跨径拱桥多采用斜拉扣挂施工技术进行拱肋节段拼装,通常扣索数量繁多、各扣索间距较密集,传统采用逐级松索的拆除方法面临施工工作量大、拆索效率低的现状,提出一种从拱脚到l/4和l/4到拱顶交替一次拆除扣索的快速拆索方法。该方法通过拆索过程中对拱肋控制点位移的影响分析,得到拆除不同位置扣索对结构受力变形的影响规律,提出扣索逐根拆除的施工方案,并从拱圈线形、扣索索力和拱圈应力三个方面对比分析了各拆索顺序的影响规律,以此确定最优的拆索方案。

基于事件触发的奇异semi-Markov跳变系统的有限时间控制

为减少不必要的网络资源传输,解决实际复杂系统的有限时间问题,提出一种基于事件触发方案的奇异semi-Markov跳变系统的有限时间控制器设计方法。在事件触发方案下,用系统的时滞表示网络诱导时延,闭环系统可以建模为一个时滞系统。首先,通过构造合适的Lyapunov-Krasovskii泛函,以严格矩阵不等式的形式给出充分条件,以使事件触发方案下的闭环系统正则、无脉冲、随机有限时间有界;然后,通过求解矩阵不等式,得到状态反馈控制器的参数;最后,给出一个数值示例,通过仿真证明所提方法的有效性。

An iterative algorithm for solving ill-conditioned linear least squares problems

Linear Least Squares（LLS） problems are particularly difficult to solve because they are frequently ill-conditioned, and involve large quantities of data. Ill-conditioned LLS problems are commonly seen in mathematics and geosciences, where regularization algorithms are employed to seek optimal solutions. For many problems, even with the use of regularization algorithms it may be impossible to obtain an accurate solution. Riley and Golub suggested an iterative scheme for solving LLS problems. For the early iteration algorithm, it is difficult to improve the well-conditioned perturbed matrix and accelerate the convergence at the same time. Aiming at this problem, self-adaptive iteration algorithm（SAIA） is proposed in this paper for solving severe ill-conditioned LLS problems. The algorithm is different from other popular algorithms proposed in recent references. It avoids matrix inverse by using Cholesky decomposition, and tunes the perturbation parameter according to the rate of residual error decline in the iterative process. Example shows that the algorithm can greatly reduce iteration times, accelerate the convergence,and also greatly enhance the computation accuracy.

Synchronization of perturbed chaotic systems via nonlinear control

Chaos synchronization of systems with perturbations was investigated.A generic nonlinear control scheme to realize chaos synchronization of systems was proposed.This control scheme is flexible and practicable,and gives more freedom in designing controllers in order to achieve some desired performance.With the aid of Lyapunov stability theorem and partial stability theory,two cases were presented:1) Chaos synchronization of the system without perturbation or with vanishing perturbations;2) The boundness of the error state for the system with nonvanishing perturbations satisfying some conditions.Finally,several simulations for Lorenz system were provided to verify the effectiveness and feasibility of our method.Compared numerically with the existing results of linear feedback control scheme,the results are sharper than the existing ones.

THE NUMERICAL SOLUTION OF A SINGULARLY PERTURBED PROBLEM FOR QUASILINEAR PARABOLIC DIFFERENTIAL EQUATION

We consider the numerical solution of a singularly perturbed problem for the quasilinear parabolic differential equation, and construct a linear three-level finite difference scheme on a nonuniform grid. The uniform convergence in the sense of discrete L2 norm is proved and numerical examples are presented.