时间敏感选项依赖下的基础设施恢复决策研究

突发事件发生后,基础设施之间的恢复依赖为恢复过程带来了严重挑战。为了能够在突发事件后高效而有序的实现基础设施恢复运行,根据相互之间的恢复依赖关系制定合理的恢复决策非常关键。本文基于网络流理论,以累积恢复效能最大化为目标,建立了时间敏感选项依赖下的恢复设计与调度决策混合整数规划模型。然后,讨论了模型在完全中心化、完全分散和信息共享决策环境下的应用方法。最后,通过真实基础设施数据集测试了模型,结果表明:(1)该模型在突发事件后的基础设施恢复决策中具有应用可行性;(2)决策环境显著影响存在恢复依赖的基础设施网络整体累积恢复效能;(3)与完全分散决策环境相比,在信息共享决策环境下独立决策的整体累积恢复效能可以得到大幅提升。     

Structure of tensor fields of the second rank generated by an incompatibility operator

There is considered the structure of fields of symmetric tensors η generated by the incompatibility operator Ink acting according to the formula Inkη = × η × . This operator which is closely related to internal stresses in bodies was considered by Kroner /1/ in application to the continuum theory of dislocations. Allied to the study of the structure of tensor fields is the problem of their restoration according to a given incompatibility and divergence as well as the decomposition into incompatible and compatible strain. For a sufficiently smooth Kröner tensor field that vanishes at infinity, by starting from the analogy with the properties of a vector field, it is shown that such a decomposition exists and is unique. In the supplement to /2/, this problem is solved in practice, where an effective algorithm is developed for the decomposition into appropriate invariant components by using projection operators. Analogous questions are examined below in application to finite domains as well as in connection with the decomposition of a tensor into deviatoric and spherical parts.     

Well‐posedness of the kinematic dynamo problem

In the framework of magnetohydrodynamics, the generation of magnetic fields by the prescribed motion of a liquid conductor in a bounded region is described by the induction equation, a linear system of parabolic equations for the magnetic field components. Outside G, the solution matches continuously to some harmonic field that vanishes at spatial infinity. The kinematic dynamo problem seeks to identify those motions, which lead to nondecaying (in time) solutions of this evolution problem. In this paper, the existence problem of classical (decaying or not) solutions of the evolution problem is considered for the case that G is a ball and for sufficiently regular data. The existence proof is based on the poloidal/toroidal representation of solenoidal fields in spherical domains and on the construction of appropriate basis functions for a Galerkin procedure. Copyright © 2012 John Wiley & Sons, Ltd.     

Removal of blur in images based on least squares solutions

We propose an image restoration method. The method generalizes image restoration algorithms that are based on the Moore–Penrose solution of certain matrix equations that define the linear motion blur. Our approach is based on the usage of least squares solutions of these matrix equations, wherein an arbitrary matrix of appropriate dimensions is included besides the Moore–Penrose inverse. In addition, the method is a useful tool for improving results obtained by other image restoration methods. Toward that direction, we investigate the case where the arbitrary matrix is replaced by the matrix obtained by the Haar basis reconstructed image. The method has been tested by reconstructing an image after the removal of blur caused by the uniform linear motion and filtering the noise that is corrupted with the image pixels. The quality of the restoration is observable by a human eye. Benefits of using the method are illustrated by the values of the improvement in signal‐to‐noise ratio and in the values of peak signal‐to‐noise ratio. Copyright © 2013 John Wiley & Sons, Ltd.     

矿尘影响下生态系统脆弱性级联传播模型分析

为了解决矿尘连续排放并迁移对地表生态系统造成的脆弱性问题,提出了基于函数地理Petri网的脆弱性级联传播模型。综合考虑污染物迁移方向和生态环境在地理空间上的关联关系,直观地构造了基于级联传播的污染Petri网。在此基础上,定义了基于VCPM的脆弱度和阈值的概念,利用两者的关系进行脆弱性级联传播分析,从而明确级联传播的三种状态。最后,以神府煤田矿尘迁移作为污染物连续排放的污染源,通过模型方法的模拟仿真分析,对生态环境系统在级联传播下的脆弱性进行了深入探讨。已有的研究方法和结果不仅在生态环境脆弱性研究领域做出了新的贡献,而且为环境的修复和重建提供了参考价值。     

A symmetry problem with applications to finance

In this paper we will consider an overdetermined problem in an unknown ring-shaped domain, and we prove that the domain has to be spherical ring. We will apply this problem to an \(n\) -dimensional toy model in the mean field game theory introduced by Lasry-Lions too. We show that if in Lasry-Lions model, the additional extra data ”the boundary is a level set” is assumed, then the region, where the solution is harmonic, has to have spherical symmetry.     

面向韧性提升的相互依赖关键基础设施网络灾后修复模型研究

科学合理制定相互依赖关键基础设施网络(Interdependent Critical Infrastructure Network, ICINs)遭灾后毁坏组件的修复计划是其安全管理的至关重要内容。本文首先明确了ICINs的韧性测度,分析了其灾后修复策略;然后基于网路流理论,以最大化ICINs的韧性为目标,构建了在有限灾后修复资源约束下,ICINs的灾后修复任务选择与调度的混合整数规划模型,并设计了遗传算法进行求解;最后通过不同规模的用例实验对模型和遗传算法进行了测试。研究表明:(1)该模型具有解决相关问题的可行性与有效性;(2)设计的遗传算法能获得质量较高的满意解,且对于大规模问题,遗传算法的求解时间与求解结果优于Cplex软件;(3)将网络之间的功能与空间相互依赖同时纳入模型中,能使ICINs的韧性达到更高。研究可为ICINs的灾后修复决策提供辅助。     

Matched asymptotic expansions for the determination of the electromagnetic field near the edge of a patch antenna

We consider a simple but representative model incorporating the main behavior of the electromagnetic field near the edge of a patch antenna. Recall that this kind of antenna is obtained by a metal patch laying on a dielectric substrate covering a ground metallic plane. The functioning principle of such an electric device is based on the matching of an N-dimensional behavior of the field outside the antenna with an (N-1)-dimensional one inside the zone limited by the patch and the ground plane, N = 3 or 2 according to the considered model. In this study, we make use of the technique of matched asymptotic expansions and computation of singularities to describe this behavior for the two-dimensional case. Proved error estimates enable us to give a rigorous background to the underlying asymptotic analysis. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)     

几种类型的K~*空间的特征

<正> §1.引言 假设非平坦的 n 维黎曼空间的曲率张量 R_(hijk)在每一点恒满足下列关系(?)其中(?)是某一向量场,同时也满足     

债务治理、地方融资平台期限错配与企业绩效——基于“43号文”的研究

本文利用我国2009~2018年2193家地方融资平台的面板数据,采用基准回归模型和中介效应模型,分析了43号文件对地方融资平台期限错配的治理效应,并进一步分析了债务治理是如何通过缓解地方融资平台期限错配最终改善企业绩效的。结果表明:(1)43号文改善了地方融资平台期限错配问题,并增加了企业绩效,这一结论在稳健性检验中也得到了验证;(2)43号文改善了省及省会(单列市)类地方融资平台的期限错配问题,并相应的改善了企业的绩效;(3)43号文改善了土木工程类和房地产类地方融资平台的期限错配问题,并相应的改善了企业的绩效。     

Electric field effect on properties of PT/epoxy nanocomposites

The structure and optic properties of PbTiO₃ nanocrystalline powder/epoxy composites are studied under different electric fields during solidification. X-ray diffraction (XRD), scattered light, ultraviolet optic absorption and second harmonic generation (SHG) of the composites are measured. Results show that the electric field has a great effect on the properties of nanocomposites. The mechanism of electric field production is discussed. Project supported by the National Advanced Materials Research Project and the Natural Science Foundation of Guangdong Province of China.     

大数据背景下基于5S的城市交通拥堵评价模型研究

近几年来,城市交通拥堵问题日益突出,极大制约了城市发展。在大数据背景下,为了准确掌握交通实时拥堵状况,改善城市交通,便利市民出行,本文深入挖掘城市交通拥堵的影响因素,构建了基于交通5S要素的城市拥堵理论模型,运用径向基函数神经网络方法工具,以上海静安寺、上海站、陆家嘴周围三大拥堵路段的交通数据集为例,验证了该模型的有效性。实验结果表明,由该模型获得的城市交通拥堵预测值与上海实际交通路况具有较好的拟合效果,表明交通5S模型与方法能够准确有效地评价城市交通拥堵。     

On the repulsion of an interface above a correlated substrate

We analyze a model of an interface fluctuating above a rough substrate. It is based on harmonic crystals, or lattice free fields, indexed by ^d , d 3. The phenomenon for which we want to get precise quantitative estimates is the repulsion effect of the substrate on the interface: the substrate is itself a random field, but its randomness is quenched (this generalizes the widely considered case of a flat deterministic substrate). With respect to [2] in which the substrate has been taken to be an IID field, here the substrate is an harmonic crystal, as the interface, and as such it is strongly correlated. We obtain the leading asymptotic behavior of the model in the limit of a very extended substrate: we show in particular that, to leading order, the effect of an IID substrate cannot be distinguished from the effect of an harmonic crystal substrate. We observe however that, unlike in the IID substrate case, annealed and quenched models display sharply different features.     

电力市场环境下计及V2G和多类型需求响应的综合能源系统多目标优化模型

园区综合能源系统(Park integrated energy system,PIES)是满足用户多种用能需求的一种重要途径,但由于内部分布式能源机组出力具有不确定性,且与负荷在时间维度上存在一定的不匹配性,限制了能源利用效率和经济效益的提升.因此,本文首先在构建耦合热电的PIES的基础上,构建了多类型需求响应模型;其次,构建了考虑风光机组出力不确定性的以系统净收益、清洁能源弃能率为多目标函数的优化模型;然后,构建了"不确定性处理-多目标处理-单目标处理"的三阶段求解模型,最后,以V2G和需求响应为考虑条件,设计多情景.算例结果表明:V2G可以为清洁能源不稳定发电提供有效备用,在一定程度上提供清洁能源利用效率;引入电热需求响应,能够改变用户负荷,增加经济效益.     

High-order harmonic generation in Ar and Ne with a 45fs intense laser field

Experimental results of high-order harmonic generation (HHG) in Ar and Ne gas driven with a 45fs Ti: sapphire laser are presented. The shortest-wavelength harmonic emission corresponding to the 91st order harmonic (8.63nm) is observed in argon. In neon, the harmonics up to order 131 (5.99nm) is also observed. The effects of gas density, laser intensity, free electron and the focusing geometry parameters of the laser beam on the process of harmonic generation are investigated. The direct experimental evidence that an increased electron density causes a degenerated harmonic radiation is obtained. Project supported by the Chinese Academy of Sciences and the High-Tech Project of China.     

Magnetic Catalysis of the P-Parity-Breaking Phase Transition of the First Order and High-Temperature Superconductivity

In the framework of a (2+1)-dimensional P-even gauge theory based on the massive Gross–Neveu model, we show that an external magnetic field induces the P-parity-breaking phase transition of the first order. A dynamical generation of the Chern–Simons term and fractional particle spin and statistics occurs at the critical point. The results in the paper can be interesting in connection with recently discovered phase transitions in high-temperature superconductors.     

Suppression of Electromagnetically Induced Free-Surface Instabilities in Liquid Metals

The work presented is devoted to studies of foundations of the suppression techniques for electromagnetically induced instabilities of the free liquid metal surfaces. Such instabilities occur, for instance, in a number of technologies for requested refinement of materials like electron beam evaporation or levitation melting, in which the electromagnetic shaping technique is applied. The instability phenomenon in our case has following magnetohydrodynamic background. High-frequency magnetic field causes Lorentz force density generation within so-called skin-layer in the liquid metal, which works as a surface pressure in turn. With increase of the electromagnetic pressure a destabilizing mechanism progresses within the liquid metal domain, which causes a bifurcation. In this paper we discuss application alternating magnetic fields to increase the bifurcation threshold by passive and active redistribution of the Lorentz force density in the near-surface layers of the liquid metal domain. A novel stabilization system on the basis of a local electromagnetic influence on the liquid metal surface in the high frequency magnetic field is presented. The experimental results are discussed. (© 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim)     

Time-Accurate CFD Predictions and Data Validation for Side Load Generation by Flow-Structure Coupling in Over-Expanded Rocket Nozzles

The present paper validates results from numerical simulations for side load generation in rocket nozzles against related data from analytical models that are presently used for rocket engine nozzle design activities.Time-accurate two- and three-dimensional turbulent Navier–Stokes (N–S) computations are performed for separated flow in deflected and ovalized nozzles as well as for nozzles under forced harmonic oscillations. Based on this comparison conclusions are drawn concerning the validity of the physical model assumptions that the analytical design methods are based on.Mathematics Subject Classification (2000) 74F10.