A Decomposition and Coordination Scheduling Method for Flow-shop Problem Based on TOC

There are many flow shop problems of throughput (denoted by FSPT) with constraints of due date in real production planning and scheduling. In this paper, a decomposition and coordination algorithm is proposed based on the analysis of FSPT and under the support of TOC (theory of constraint). A flow shop is at first decomposed into two subsystems named PULL and PUSH by means of bottleneck. Then the subsystem is decomposed into single machine scheduling problems,so the original NP-HARD problem can be transferred into a serial of single machine optimization problems finally. This method reduces the computational complexity, and has been used in a real project successfully.

3D Numerical Simulation of Overbank Flow in Non-Orthogonal Curvilinear Coordinates

The velocity field in meandering compound channels with overhank flow is highly three dimensional. To date, its features have been investigated experimentally and little research has been undertaken to investigate the feasibility of reproducing these velocity fields with computer models. If computer modeling were to prove successful in this context, it could become a useful prediction technique and research tool to enhance our understanding of natural river dynamics. A 3-D k-E turbulence hydrodynamic model in curvilinear coordinates is established to simulate the overhank flow. The bodyfitted coordinate is adopted in the horizontal plane, the part grid is adopted in the vertical direction, and the wall-function method is employed to simulate the bed resistance. The model is applied to the simulation of the meandering channel with straight flood plain banks, and the main velocities and secondary velocities for both the longitudinal and cross sections are presented. Comparison and analysis show that the results of simulation are fit to reflect the results of experiment. These results show the application value of the model to 3D overhank flow.

Vertical 2D Modeling of Free Surface Flow with Hydrodynamic Pressure Using SIMPLE Arithmetic in σ Coordinates

A numerical model for shallow water flow has been developed based on the unsteady Reynolds-averaged Navier-Stokes equations with the hydrodynamic pressure instead of hydrostatic pressure assumption. The equations are transformed into the σ-coordinate system and the eddy viscosity is calculated with the standard k-ε turbulence model. The control volume method is used to discrete the equations, and the boundary conditions at the bed for shallow water models only include vertical diffusion terms expressed with wall functions. And the semi-implicit method for pressure linked equation arithmetic is adopted to solve the equations. The model is applied to the 2D vertical plane flow of a current over two steep-sided trenches for which experiment data are available for comparison and good agreement is obtained. And the model is used to predicting the flow in a channel with a steep-sided submerged breakwater at the bottom, and the streamline is drawn.

Staggered Calculation of Turbulent Flows Over a 3D Bluff Body Using Curvilinear Nonorthogonal Coordinates

A finite difference method is developed to predict turbulent flows over 3D bluffbodies. The K-ε turbulence model with Launder and Spalding's wall treatment isemployed. The solution alsorithm is based on a body fitted nonorthogonalcurvilinear eourdinate system and a stagsered grid arrangement. The covariantvelocity components are chosen as dependent variables. Convective fluxes aredescribed by the Power haw Scheme. The grids are generated with an ellipticgrid generator using control functions. Results obtained are compared withexporiment measurements and other calculations.

Coordinated restoration optimization of power-gas integrated energy system with mobile emergency sources

In an integrated energy system(IES) composed of multiple subsystems, energy coupling causes an energy supply blockage or shutdown in one subsystem, thereby affecting the energy flow distribution optimization of other subsystems.The energy supply should be globally optimized during the IES energy supply restoration process to produce the highest restoration net income. Mobile emergency sources can be quickly and flexibly connected to supply energy after an energy outage to ensure a reliable supply to the system, which adds complexity to the decision. This study focuses on a powergas IES with mobile emergency sources and analyzes the coupling relationship between the gas distribution system and the power distribution system in terms of sources, networks, and loads, and the influence of mobile emergency source transportation. The influence of the transient process caused by the restoration operation of the gas distribution system on the power distribution system is also discussed. An optimization model for power-gas IES restoration was established with the objective of maximizing the net income. The coordinated restoration optimization decision-making process was also built to realize the decoupling iteration of the power-gas IES, including system status recognition, mobile emergency source dispatching optimization, gas-to-power gas flow optimization, and parallel intra-partition restoration scheme optimization for both the power and gas distribution systems. A simulation test power-gas IES consisting of an 81-node medium-voltage power distribution network, an 89-node medium-pressure gas distribution network, and four mobile emergency sources was constructed. The simulation analysis verified the efficiency of the proposed coordinated restoration optimization method.

变截面半圆通道内超临界二氧化碳热工水力性能研究

建立了不同半圆通道的数学和物理模型,并通过与实验数据的比较,验证了所建立模型的准确性。研究了超临界二氧化碳(S-CO_(2))在等截面半圆通道、渐扩型和渐缩型通道内的热工水力换热性能,并分析了不同通道和压力对S-CO_(2)在变截面半圆通道内的热工水力性能的影响。结果表明:相较于均匀截面半圆通道,渐扩型通道恶化传热,渐缩型通道强化传热;入口和出口半径比为1.0:0.5的渐缩型半圆通道的总体换热系数最大提升了39.93%,流动传热综合性能评价因子PEC最大为1.346;当压力越靠近临界压力或热通量较低时,传热性能越高。最后,从场协同性和湍动能分布的角度解释了渐缩型变截面通道强化传热的原因。研究结果可为S-CO_(2)循环系统冷却器的设计与优化提供新的思路和理论指导。

基于UNet的翼型可压缩流场机器学习推理方法

为进一步提升高雷诺数、大迎角(Angle of attack,AoA)和高马赫数下的翼型可压缩流场预测精度和效率,本文提出了一种基于坐标转换方法和UNet神经网络的机器学习推理方法。首先,提出了用于数据前处理的坐标转换方法,将计算流体力学中的物理量和网格信息转换成神经网络空间信息,使流场信息的分布更符合神经网络的输入要求。其次,建立了新型深度UNet神经网络,使模型学习到翼型流场精细复杂的局部流动特征。本文将两种方法结合,建立了翼型可压缩流场机器学习推理方法,得到快速高精度的推理模型。最后,对不同种类翼型的流场与气动力进行预测分析,并与传统机器学习方法预测的结果进行比较。结果表明,本文提出的机器学习推理方法能够较好地预测翼型的可压缩流场,并且能够更好地捕捉高雷诺数下的复杂流动行为以及预测大迎角、高马赫数条件下的流动分离和激波现象。

基于凸包理论的含风电电力系统负荷恢复方案优化

大停电事故后,合理的负荷恢复策略对加快电力系统恢复、减少停电损失具有重要意义。针对标准交流潮流方程的非凸性导致负荷恢复模型求解效率低的问题,提出了基于凸包理论的含风电电力系统负荷恢复方案优化方法。首先,简要介绍了凸包理论以及非线性函数的凸包构建方法。其次,针对风电出力的不确定性,采用条件风险价值理论处理风电波动带来的风险,进而建立了直角坐标系下基于凸包理论的电力系统负荷恢复二阶锥优化模型,其中,交流潮流方程中的非线性项采用凸包表达。针对无法精确确定凸包参数的问题,提出了基于迭代更新的参数优化方法,减少因凸包引入的松弛误差。所提出的模型为混合整数二阶锥规划模型,可采用商业求解器高效求解。最后,采用IEEE 39节点系统和改进的广东电力系统验证了所提出模型的有效性。

高焓流动中的可压缩颗粒两相流并行求解器:数值方法及其验证

在极端力学环境下可压缩点力颗粒两相流理论方程的基础上,提出一种基于动态链表数组的并行颗粒求解器,使其与可压缩流体求解器耦合。与基于欧拉坐标系的携带流体相不同,基于拉格朗日坐标系的求解器采用动态链表数组对弥散颗粒相进行内存分配,可以解决因使用全局数组解决拉格朗日/欧拉坐标系转换带来的弥散颗粒群内存利用率低和计算效率低下问题。最后对多物理效应的可压缩颗粒两相流求解器进行验证,并在马赫数渐进趋于零的情况下,对两个不可压缩槽道颗粒湍流标模进行验证。

基于遗传算法的高峰时段车站协同限流方法

车站限流是缓解城市轨道交通高峰客流拥挤的有效应对措施。然而,目前实际应用的限流措施缺乏对同线路相邻车站的协同配合的考虑,限流效果有待进一步提升。综合考虑乘客、列车、车站三者的交互关系,依据列车在车站的发车时间间隔,对高峰时段的列车时刻表进行时间离散化,将离散化的时段作为基本研究时段,提取对应的车站乘客到达量。从供需双方的角度出发,以乘客总延误时间最小化和旅客周转量最大化为优化目标,在考虑列车运输能力、客流控制强度、车站服务水平的同时,引入列车剩余运输能力作为约束条件,平衡不同车站的客流需求,构建车站协同限流优化模型。针对多目标函数求解的复杂性,设计1种嵌入式遗传算法对模型进行求解,平衡多目标函数之间最优解的冲突。以南京地铁三号线高峰时段为例,与不采取协同限流的情景(先到先服务)进行对比分析。结果表明:在乘客总周转量提升1%的情况下,乘客延误人数下降了2.3%,乘客总延误时间降低了4.3%,拥挤车站的延误人数显著降低,延误人数的时空分布更加平衡。为了验证算法的有效性和模型的稳定性,将遗传算法与Gurobi求解器进行算法对比,并对关键参数列车满载率进行灵敏度分析,提出的遗传算法更能兼顾双优化目标,有利于缓解高峰时段大客流延误。

基于改进薄板样条运动模型的人脸动画算法

面部动画在电影、游戏、虚拟现实等领域起着关键作用,对于实现逼真、生动的人脸动画和情感传达至关重要。当面临面部形状、姿态、表情等多个变化因素时,虽然通过薄板样条非线性变换可以获得较好的运动估计结果,但在处理面部复杂纹理和嘴部运动时存在运动估计不精细的问题,需要更强大的图像修复能力。因此,提出一种基于改进薄板样条运动模型(TPSMM)的人脸动画算法。首先,在TPSMM的基础上引入一种Farneback光流金字塔算法,通过与薄板样条变换和背景仿射变换相结合,使得人脸局部运动估计更精准;其次,为了更真实地恢复缺失区域的细节纹理信息,提出一种多尺度细节感知网络,该网络在编码器中通过嵌入通道注意力(ECA)模块减少源图像因多层下采样而导致的人脸细节信息丢失,在解码器中利用坐标注意力(CA)模块来有效捕获运动估计特征图中不同位置的重要特征,提高人脸图像的生成质量。实验结果表明,相比一阶段运动模型(FOMM)、关节动画的运动表示法(MRAA)、TPSMM等,该算法在MUG、UvA-Nemo和Oulu-CASIA数据集上的L1、平均关键点距离(AKD)、平均欧氏距离(AED)数值均达到最优,平均分别为0.0129、0.923、0.00099。

考虑线路能力协调利用的车流径路与配空组织优化模型

为提高铁路整体通过能力,均衡利用路网中各线路,应对愈发波动的运输市场,开展考虑线路能力协调利用的重空车流协调优化模型研究。首先,对线路能力协调利用的实现机理进行研究,在考虑流平衡约束、配空约束、线路能力约束基础上,增加考虑铁路线路能力协调利用约束,同时在优化目标中增加紧张线路的使用成本,构建考虑线路能力协调利用的重空车流组织优化模型,以实现在优化车流径路与空车调配方案的同时兼顾铁路线路的协调利用。其次,在此基础上设计拉格朗日松弛算法,对线路能力约束与能力协调性约束松弛,将原问题分解为车流径路子问题、空车调配子问题和虚拟车流量子问题,进而降低了问题求解难度。再次,通过5组算例对算法的有效性进行验证,案例结果说明,设计的拉格朗日松弛算法在求解大规模算例时效率优于商业求解软件Gurobi。最后,设计了包含36个车站56条线路的实际案例,算法求解耗时4757.7 s,运输组织综合成本为29535803元,通过对求解结果分析,与传统优化模型相比该模型优化结果在运输成本仅增加1.56%的前提下能力紧张的线路数量由17条缩减至12条,降低了29.4%,同时空车调配符合就近配空的原则。研究结果表明,该模型可以有效缓解铁路能力紧张情况,促进铁路线路能力的协调利用。

资本管制的理论依据与实践选择

全球金融危机造成国际资本剧烈波动并严重影响各国经济,对新兴市场国家的影响尤为明显,引发对资本管制政策必要性的重新思考。而重大突发公共卫生事件暴发导致的新一轮资本流出给新兴市场国家带来的巨大冲击,以及中国不断推进的金融市场双向开放引起的对全球金融状况的敏感性逐步增加,都凸显出合理使用资本管制政策的重要意义。通过梳理近年来关于资本管制政策实施的理论基础、国际货币基金组织对待资本管制政策的态度、新兴市场国家资本账户管理的经验,以及中国资本账户开放实践等方面的文献,发现现有文献在资本管制政策的有效性上尚未达成共识,未来应从资本管制政策与其他宏观经济政策的配合使用、资本管制政策的溢出效应与国际经济政策协调等方面进一步开展研究。

Simulation and Analysis of Cascading Faults in Integrated Heat and Electricity Systems Considering Degradation Characteristics

Cascading faults have been identified as the primary cause of multiple power outages in recent years.With the emergence of integrated energy systems(IES),the conventional approach to analyzing power grid cascading faults is no longer appropriate.A cascading fault analysis method considering multi-energy coupling characteristics is of vital importance.In this study,an innovative analysis method for cascading faults in integrated heat and electricity systems(IHES)is proposed.It considers the degradation characteristics of transmission and energy supply com-ponents in the system to address the impact of component aging on cascading faults.Firstly,degradation models for the current carrying capacity of transmission lines,the water carrying capacity and insulation performance of thermal pipelines,as well as the performance of energy supply equipment during aging,are developed.Secondly,a simulation process for cascading faults in the IHES is proposed.It utilizes an overload-dominated development model to predict the propagation path of cascading faults while also considering network islanding,electric-heating rescheduling,and load shedding.The propagation of cascading faults is reflected in the form of fault chains.Finally,the results of cascading faults under different aging levels are analyzed through numerical examples,thereby verifying the effectiveness and rationality of the proposed model and method.

大规模风电并网后江苏电网柔直换流站与UPFC的有功功率协调控制方法

随着“双碳”战略的提出与实施,我国将着力建设以新能源为主的新型电力系统。然而,风电等新能源大规模并网将给具有交直流混联特征的新型电力系统带来威胁与挑战。通过以十四五规划末期的江苏电网为例进行分析,发现在大规模风电并网背景下,江苏电网中部分“南北向”500 kV交流输电线路N-1后负载过重的问题亟待解决。为此,基于综合灵敏度计算方法,提出了一种综合利用柔直换流站和统一潮流控制器的有功功率协调控制方法,用于改善系统潮流分布并消除潜在的线路过载。最后,以江苏电网为例进行了仿真分析,对苏州500 kV统一潮流控制器、白鹤滩-江苏直流和某规划中三端柔直换流站进行了有功协调控制。结果表明,所提协调控制方法应用于江苏电网时可有效解决交流输电通道N-1后负载过重问题,且相比于典型最优化方法在计算速度上具有优势。

计及备用风险性的新型电力系统源网协同安全经济调度

为合理利用源侧备用资源,提出基于随机潮流和半不变量法的备用风险评估指标,以准确量化因备用不足而造成的潮流越限风险;为了实现源侧备用资源和网侧可控资源的协同优化,将网侧有载调压变压器和电容器组无功补偿装置纳入决策变量,以系统运行成本最低和系统运行越限风险指标值最小为优化目标,构建计及备用风险性的新型电力系统源网协同安全经济调度模型;将布朗运动和莱维飞行随机游走机制融入多目标微分进化算法,设计新型的布朗-莱维多目标微分进化算法,对模型进行高效求解。算例分析结果验证了所提方法的有效性和优越性。

FLOW-SHOP网络交链系统的无阻塞最优协调控制

用极大代数模块网络法 ,建立了 FLOW-SHOP网络交链系统的数据结构模型 .在这个模型上 ,提出了寻找交链系统特征值的周期同步算法和寻找特征向量的递归协调算法 ,结果证明 ,FLOW-SHOP网络交链系统的无阻塞最优协调控制是一类线性状态反馈且最优协调控制系统的优控参数可以直接列写 ,最后的例子指出 。

基于三维坐标系的动车组运检计划算法模型

构建以动车组-交路\修程-天数三维坐标系数学模型,全面考虑动车组运用与检修计划编制的优化目标和约束条件,构建动车组运检计划优化编制的数学优化模型。在给定动车组数量、交路计划的前提下,根据动车所实际情况,以“天”为最小的计划编制时间单位,通过控制换车次数,以检修时剩余里程为追求目标,阐述并规范运检计划算法实现流程,实现大空间分段式快速粒子群优化算法完成动车组运检计划的快速给定。

高速公路实时交通流模糊逻辑优化控制系统设计

针对高速公路交通流特征复杂多变,并受到天气、道路状况和车辆类型等多种因素影响的问题,设计了一种新的高速公路实时交通流模糊逻辑优化控制系统,包括硬件和软件两部分;在硬件方面,设计了车流控制模块、无线传输车载终端、实时交通流逻辑调度模块和模糊控制器模块,并确定了它们之间的实时连接关系;在软件方面,求解了交通流逻辑控制条件,联合了高速公路实时通行相位条件,调节了模糊控制器,并根据高速公路交通路网模型推导了交通流优化控制条件的求解表达式;实验结果表明,该系统可以解决逻辑协调错误的问题,并有效控制高速公路车流量。

长江中下游平原河网地区畅流活水方案研究

新时期下水环境治理从单一的水环境污染治理转向“三水统筹”,本文以常熟市城区为研究对象,通过河网水动力数学模型对全城活水、分区活水和局部强化活水三大类型的畅流活水方案进行了模拟研究。结果表明,周期性开闭闸门、自流引清、有序冲排的方法能有效增强河流水体流动性,为改善城区水环境质量提供保障,并为其他长江中下游平原河网地区实现“三水统筹”提供了新思路。