An Explicit-Implicit Mixed Staggered Asynchronous Step Integration Algorithm in Structural Dynamics

Many engineering applications need to analyse the system dynamics on the macro and micro level,which results in a larger computational effort.An explicit-implicit asynchronous step algorithm is introduced to solve the structural dynamics in multi-scale both the space domain and time domain.The discrete FEA model is partitioned into explicit and implicit parts using the nodal partition method.Multiple boundary node method is adopted to handle the interface coupled problem.In coupled region,the implicit Newmark coupled with an explicit predictor corrector Newmark whose predictive wave propagates into the implicit mesh.During the explicit subcycling process,the variables of boundary nodes are solved directly by dynamics equilibrium equation.The dissipation energy is dynamically determined in accordance with the energy balance checking.A cantilever beam and a building two numerical examples are proposed to verify that the method can greatly reduce the computing time while maintaining a high accuracy.

Energy-Work Connection Integration Scheme for Nonholonomic Hamiltonian Systems

This paper focuses on studying a new energy-work relationship numerical integration scheme of nonholo-nomie Hamiltonian systems.The signal-stage numerical,multi-stage and parallel composition numerical integrationschemes are presented.The high-order energy-work relation scheme of the system is constructed by a parallel connectionof n multi-stage schemes of order 2,its order of accuracy is 2n.The connection,which is discrete analogue of usual case,between the change of energy and work of nonholonomic constraint forces is obtained for nonholonomic Hamiltoniansystems.This paper also gives that there is smaller error of the scheme when taking a large number of stages than a lessone.Finally,an applied example is discussed to illustrate these results.

RETROSPECTIVE TIME INTEGRAL SCHEME AND ITS APPLICATIONS TO THE ADVECTION EQUATION

To put more information into a difference scheme of a differential equation for making an accurate prediction, a new kind of time integration scheme, known as the retrospective (RT) scheme, is proposed on the basis of the memorial dynamics. Stability criteria of the scheme for an advection equation in certain conditions are derived mathematically. The computations for the advection equation have been conducted with its RT scheme. It is shown that the accuracy of the scheme is much higher than that of the leapfrog (LF) difference scheme.

Unifying the theory of integration within normal-,Weyl- and antinormal-ordering of operators and the s-ordered operator expansion formula of density operators

By introducing the s-parameterized generalized Wigner operator into phase-space quantum mechanics we invent the technique of integration within s-ordered product of operators （which considers normally ordered, antinormally ordered and Weyl ordered product of operators as its special cases）. The s-ordered operator expansion （denoted by s…s ） formula of density operators is derived, which isρ=2/1-s∫d^2β/π〈-β｜ρ｜β〉sexp{2/s-1（s｜β｜^2-β＊α＋βa-αα）}s The s-parameterized quantization scheme is thus completely established.

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.

Topology Discovery Sub-Layer for Integrated Terrestrial-Satellite Network Routing Schemes

With the booming development of terrestrial network, scaling terrestrial network over satellite network to build Integrated Terrestrial-Satellite Network(ITSN) and meanwhile to provide the global Internet access, has become ever more attractive. Naturally, the widely and successfully used terrestrial routing protocols are the promising protocols to integrate the terrestrial and satellite networks. However, the terrestrial routing protocols, which rely on propagating routing messages to discover New Network Topology(NNT) in the terrestrial network with rare topology changes, will suffer from overly numerous routing messages in satellite network whose topology frequently changes as satellites move. In this paper, a Topology Discovery Sub-layer for ITSN Routing Schemes(TDS-IRS) is firstly proposed to avoid the propagation of numerous routing messages by taking advantage of the movement predictability of satellite and the requirements of routing schemes to discover NNT in advance of topology change. Secondly, a Weighted Perfect Matching based Topology Discovery(WPM-TD) model is designed to conduct the NNT discovery on the ground. Thirdly, this paper builds a testbed with real network devices and meanwhile interconnect that testbed with real Internet, to validate that RS-TDS can discover NNT immediately with the less on-board overhead compared with optimized routing schemes. Finally, different network scenarios are applied to validate the WPM-TD, i.e., the core module of TDS-IRS. Extensive experiments show WPM-TD can work efficiently, avoiding the invalid NNT discovery and decreasing 20% ~ 57% of potential topology changes, which can also improve up to 47% ~ 105% of network throughput.

Development of Non-Dissipative Direct Time Integration Method for Structural Dynamics Application

A direct time integration scheme based on Gauss-Legendre quadrature is proposed to solve problems in linear structural dynamics.The proposed method is a oneparameter non-dissipative scheme.Improved stability,accuracy,and dispersion characteristics are achieved using appropriate values of the parameter.The proposed scheme has second-order accuracy with and without physical damping.Moreover,its stability,accuracy,and dispersion are analyzed.In addition,its performance is demonstrated by the two-dimensional scalar wave problem,the single-degree-of-freedom problem,two degrees-of-freedom spring system,and beam with boundary constraints.The wave propagation problem is solved in the high frequency wave regime to demonstrate the advantage of the proposed scheme.When the proposed scheme is applied to solve the wave problem,more accurate solutions than those of other methods are obtained by using the appropriate value of the parameter.For the single-degree-offreedom system,two degrees-of-freedom system,and the time responses of beam,the proposed scheme can be used effectively owing to its high accuracy and lower computational cost.

AN INTEGRATION METHOD WITH FITTING CUBIC SPLINE FUNCTIONS TO A NUMERICAL MODEL OF 2ND-ORDER SPACE-TIME DIFFERENTIAL REMAINDER——FOR AN IDEAL GLOBAL SIMULATION CASE WITH PRIMITIVE ATMOSPHERIC EQUATIONS

In this paper,the forecasting equations of a 2nd-order space-time differential remainder are deduced from the Navier-Stokes primitive equations and Eulerian operator by Taylor-series expansion.Here we introduce a cubic spline numerical model(Spline Model for short),which is with a quasi-Lagrangian time-split integration scheme of fitting cubic spline/bicubic surface to all physical variable fields in the atmospheric equations on spherical discrete latitude-longitude mesh.A new algorithm of"fitting cubic spline—time step integration—fitting cubic spline—……"is developed to determine their first-and2nd-order derivatives and their upstream points for time discrete integral to the governing equations in Spline Model.And the cubic spline function and its mathematical polarities are also discussed to understand the Spline Model’s mathematical foundation of numerical analysis.It is pointed out that the Spline Model has mathematical laws of"convergence"of the cubic spline functions contracting to the original functions as well as its 1st-order and 2nd-order derivatives.The"optimality"of the 2nd-order derivative of the cubic spline functions is optimal approximation to that of the original functions.In addition,a Hermite bicubic patch is equivalent to operate on a grid for a 2nd-order derivative variable field.Besides,the slopes and curvatures of a central difference are identified respectively,with a smoothing coefficient of 1/3,three-point smoothing of that of a cubic spline.Then the slopes and curvatures of a central difference are calculated from the smoothing coefficient 1/3 and three-point smoothing of that of a cubic spline,respectively.Furthermore,a global simulation case of adiabatic,non-frictional and"incompressible"model atmosphere is shown with the quasi-Lagrangian time integration by using a global Spline Model,whose initial condition comes from the NCEP reanalysis data,along with quasi-uniform latitude-longitude grids and the so-called"shallow atmosphere"Navier-Stokes primitive equations in the spherical coordinates.The Spline Model,which adopted the Navier-Stokes primitive equations and quasi-Lagrangian time-split integration scheme,provides an initial ideal case of global atmospheric circulation.In addition,considering the essentially non-linear atmospheric motions,the Spline Model could judge reasonably well simple points of any smoothed variable field according to its fitting spline curvatures that must conform to its physical interpretation.

A Novel Pipelining Encryption Hardware System with High Throughput and High Integration for 5G

This paper presents a ZUC-256 stream cipher algorithm hardware system in order to prevent the advanced security threats for 5 G wireless network.The main innovation of the hardware system is that a six-stage pipeline scheme comprised of initialization and work stage is employed to enhance the solving speed of the critical logical paths.Moreover,the pipeline scheme adopts a novel optimized hardware structure to fast complete the Mod(231-1)calculation.The function of the hardware system has been validated experimentally in detail.The hardware system shows great superiorities.Compared with the same type system in recent literatures,the logic delay reduces by 47%with an additional hardware resources of only 4 multiplexers,the throughput rate reaches 5.26 Gbps and yields at least 45%better performance,the throughput rate per unit area increases 14.8%.The hardware system provides a faster and safer encryption module for the 5G wireless network.

OPTIMAL SCHEME FOR SEQUENTIAL COMPUTATIONS OF F_m(z) INTEGRALS IN AB INITIO CALCULATIONS----COMBINATORY USE OF UPWARD AND DOWNWARD RECURSIONS

The quantitative rules of the transfer and variation of errors,when the Gaussian integral functions F.(z) are evaluated sequentially by recurring,have been expounded.The traditional viewpoint to negate the applicability and reliability of upward recursive formula in principle is amended.An optimal scheme of upward-and downward-joint recursions has been developed for the sequential F(z) computations.No additional accuracy is needed with the fundamental term of recursion because the absolute error of Fn(z) always decreases with the recursive approach.The scheme can be employed in modifying any of existent subprograms for Fn<z> computations.In the case of p-d-f-and g-type Gaussians,combining this method with Schaad's formulas can reduce,at least,the additive operations by a factor 40%;the multiplicative and exponential operations by a factor 60%.

制导控制系统半实物仿真总体方案设计及集成联试

半实物仿真作为一个大型分布式仿真系统,其总体方案的设计优劣和集成联试的是否顺利,直接影响了系统性能指标的表现和建设目标的实现。归纳总结了总体方案设计的工作内容,分析了实时性、兼容性、扩展性和安全性的性能要求;给出了包括功能层次、运行机制和结构组成在内的典型半实物仿真系统总体方案;概括了仿真系统的集成联试内容,总结了典型系统的集成联试步骤,给出了系统验收测试的内容和系统可信度评估方法。

高速铁路列车运行图一体化自动编制方法研究

高速铁路列车运行图编制不仅要在图面上生成列车运行线,还要考虑客运需求、车底交路运用、车站股道运用等问题,影响因素众多,且各影响因素相关性较强,因而我国高速铁路列车运行图一直以来都采用人工铺画方式,缺少计算机一体化自动编制方法。为进一步提高高速铁路运行图编制效率,在借鉴人工编图经验的基础上,提出基于车底交路方案、列车结构方案及调整策略的高速铁路列车运行图一体化自动编制流程,同时生成列车时刻表、车底交路方案、车站股道运用方案。针对不易处理的列车运行图结构优化问题,设计微观站场进路占用策略与运行图优化编制模型,并以京沪高速铁路为例进行验证,用时48 h重新铺画运行图,各项指标与真实运行图相近,大幅减少了现有运行图编制模式对人力物力的消耗,为高速铁路列车运行图编制提供一种自动化的理论与技术支撑。

偏好异质性、农户参与式方案创设与养殖废弃物资源化利用——来自养殖户种养结合的选择实验

生态补偿政策构成的农业环境方案对于废弃物资源化利用具有激励作用,但现行补偿政策方案可能存在推广瓶颈,突破瓶颈的关键在于了解农户的政策选择偏好。以养殖废弃物肥料化还田为例,通过选择实验法构建了由4个政策属性组合而成的备选政策情境,结合江苏省346户生猪养殖户实验数据,运用Mixed Logit模型检验了补偿政策的选择偏好及协同互补效应。结果表明:(1)养殖户对选择实验方案中的服务类、收入类和价格类补偿政策的偏好程度更高,而对于技术支持类补偿政策不具备明显偏好;(2)养殖户环保认知与风险特征是上述政策偏好异质性的重要来源,风险偏好型和环保认知水平高的养殖户对各类补偿政策方案的接受意愿更高;(3)技术支持、外包服务同收入类、价格类补偿政策之间呈现显著的互补性。根据“重视多元化补偿,强化正协同效应”原则,本文创设了针对养殖废弃物还田利用的推广方案,旨在优化和完善现行的生态补偿政策体系,打好相关政策措施的“组合拳”。

基于积分分析方法对聚变堆启动氚量与所需氚增殖比的评估

托卡马克聚变堆的主要发展方式包括混合堆、纯聚变堆。关于托卡马克聚变堆氚自持的研究,国内外主要采用平均滞留时间方法进行研究,并且针对聚变功率较低的混合堆的氚自持研究较少。本工作采用更符合实际的积分分析方法分析了混合堆、纯聚变堆氚自持的启动氚量、氚增殖比(TBR)要求。研究结果表明:启动氚量、备用氚量与聚变功率具有线性关系,所需TBR与聚变功率呈反比例关系;混合堆聚变功率较低,所需TBR较高,工程实现所需TBR挑战较大,需要通过限制长期氚滞留量以降低所需TBR要求;纯聚变堆聚变功率高,所需TBR较低,工程实现所需TBR挑战较小,但备用氚需求达数十千克,应考虑氚系统的冗余设计或提高氚系统的可靠性、可维护性,以降低备用氚的使用规模;运行因子是聚变堆的一个重要设计指标,在此着重分析了运行因子对所需TBR的影响,并重新定义了一个聚变堆氚自持的关系式,以突出运行因子对氚自持的重要影响。

基于天窗基本单元的编组站天窗方案优化研究

编组站接发列车方向多、数量大,机车换挂和调车作业频繁,直接影响施工维修作业。既有固定天窗时长的天窗方案,难以兼顾维修施工作业和运输工作连续性需求,导致天窗兑现率低,增加安全隐患,研究提出基于天窗基本单元的编组站天窗方案优化方法。根据各维修养护工种作业特性、编组站工作人员数量及效率等因素,划分天窗基本单元;考虑编组站维修养护与运输组织需求,以效用、作业完成率和天窗阈值利用率最优为目标,以时序关系为约束,建立基于阈值的天窗方案多目标优化模型,并利用数学软件进行求解;以成都北编组站为例,验证模型的有效性,结果表明,通过合理优化天窗方案,天窗兑现率达100%,有助于缓解编组站维修与运输之间的冲突。

改进蜉蝣算法求解工艺规划与调度集成问题

针对工艺规划与调度集成问题(IPPS),基于AND/OR析取图和“组合”的概念以最小化最大完工时间为优化目标建立数学模型;设计一种整数编码方案,该方案无需预先为工件生成加工路径,可同时处理工艺规划与调度问题,由于初始解对算法的寻优能力的影响,在种群初始化时考虑机器的负荷以提高初始种群的质量;解码时采用插空的方法生成活跃调度,以缩短工件整体的加工时间;离散蜉蝣算法实现求解IPPS,采用Metropolis准则接收较差的解,引入自适应因子提高算法的收敛速度,设计局部搜索算法提高算法的精度。最后通过大规模基准算例进行实验并与其他算法对比分析,验证该算法有较好寻优性能。

提高工业厂房自然通风效率的有效方法研究

本文探讨了工业厂房自然通风效率提高的重要性,围绕工业厂房的生产需求,提出了提高工业厂房自然通风效率的整合方案,并且通过工业厂房自然通风效率整合方案在经济效益、通风效率以及能源消耗率等方面的比较,构建了提高工业厂房自然通风效率的有效策略,旨在为满足可持续发展的需求和工业生产的实际需求提供参考性意见。

重庆轨道交通一体化运营调度系统研究

在轨道交通“多网融合”与多主体协同运营的新形势下,为实现不同交通网络、不同线路之间的高效协同与衔接,有必要构建面向一体化运营背景下的多层级轨道交通运营调度系统。以重庆轨道交通一体化运营调度系统构建为例,在总结重庆轨道交通运营调度现状的基础上,通过分析重庆轨道交通运营调度需求与目标,从总体架构、功能定位、协调机制、协同模式等方面,构建重庆轨道交通一体化运营调度指挥系统方案,提出面向重庆远期交通规划的多主体协同运营调度中心设置方案,并基于大数据平台和云计算技术,设计重庆轨道交通一体化运营调度指挥平台技术方案,以实现不同运营主体之间运营调度指挥的协调,为多层级轨道交通多主体之间线路互联互通运营奠定基础。

面向四网融合的大型铁路枢纽规划重点问题探讨

新时代开展面向“四网融合”的大型铁路枢纽规划是落实交通强国铁路先行规划纲要的重要工作。在解读“四网融合”内涵并剖析其对铁路枢纽规划的内在要求基础上,针对枢纽总图研究范围、枢纽总图格局、客运系统布局及分工、生产力布局、高速铁路及城际铁路引入、既有铁路资源利用等重点问题开展研究,并结合案例进行分析:在“为铁路服务”的基础上应强化“以人民为中心”“为城市服务”的规划理念;总图研究范围应逐步拓展至都市圈;总图格局应当推进“客内货外”“互联互通”;客运系统应“多点布局”,加强与国土空间规划、综合交通规划的耦合,客运站分工应“多点到发”“兼顾高普”“分向把口”;生产力布局应考虑不同层次网络资源共享;高速铁路、城际铁路应尽量实现“进城”;充分利用枢纽内铁路资源,研究利用既有铁路开行市域(郊)列车。

一体化保温方案联合ERAS手术室护理在肾结石术中的应用效果

目的 分析一体化保温方案联合快速康复外科(ERAS)手术室护理在肾结石手术患者中的应用效果。方法 选取2022年3月至2023年11月在我院采取手术治疗的肾结石患者92例,采取随机法中的掷硬币法进行分组,观察组(n=46)采用一体化保温方案联合ERAS手术室护理,对照组采用(n=46)常规手术室护理,比较两组护理效果。结果 观察组手术完成时和术后30 min体温高于对照组(P<0.05)。观察组并发症发生率6.52%低于对照组的23.91%(P<0.05)。观察组手术时间及各项术后恢复时间均短于对照组(P<0.05)。结论 一体化保温方案联合ERAS手术室护理可显著提升肾结石手术患者的术中保温效果,利于维持其体温稳定,减少并发症,并能够促进其快速康复。