Feedback control scheme of traffic jams based on the coupled map car-following model

Based on the pioneering work of Konishi et al. [Phys. Rev. E （1999） 60 4000], a new feedback control scheme is presented to suppress traffic jams based on the coupled map car-following model under the open boundary condition. The effect of the safe headway on the traffic system is considered. According to the control theory, the condition under which traffic jams can be suppressed is analyzed. The results are compared with the previous results concerning congestion control. The simulations show that the suppression performance of our scheme on traffic jams is better than those of the previous schemes, although all the schemes can suppress traffic jams. The simulation results are consistent with theoretical analyses.

A new coupled map car-following model considering drivers' steady desired speed

Based on the pioneering work of Konishi et al., in consideration of the influence of drivers＇ steady desired speed ef/ect on the traffic flow, we develop a new coupled map car-following model in the real world. By use of the control theory, the stability condition of our model is derived. The validity of the present theoretical scheme is verified via numerical simulation, confirming the correctness of our theoretical analysis.

A control method for congested traffic in the coupled map car-following model

Based on the pioneer work of Konishi et al, a new control method is presented to suppress the traffic congestion in the coupled map （CM） car-following model under an open boundary. A control signal concluding the velocity differences of the two vehicles in front is put forward. The condition under which the traffic jam can be contained is analyzed. The results axe compared with that presented by Konishi et al [Phys. Rev. 1999 E 60 4000-4007]. The simulation results show that the temporal behavior obtained by our method is better than that by the Konishi＇s et al. method, although both the methods could suppress the traffic jam. The simulation results are consistent with the theoretical analysis.

Modified coupled map car-following model and its delayed feedback control scheme

A modified coupled map car-following model is proposed, in which two successive vehicle headways in front of the considering vehicle is incorporated into the optimal velocity function. The steady state under certain conditions is obtained. An error system around the steady state is studied further. Moreover, the condition for the state having no traffic jam is derived. A new control scheme is presented to suppress the traffic jam in the modified coupled map car-following model under the open boundary. A control signal including the velocity differences between the following and the considering vehicles, and between the preceding and the considering vehicles is used. The condition under which the traffic jam can be well suppressed is analysed. The results are compared with that presented by t^onishi et al. （the KKH model）. The simulation results show that the temporal behaviour obtained in our model is better than that in the KKH model. The simulation results are in good agreement with the theoretical analysis.

Considering Backward Effect in Coupled Map Car-Following Model

Based on the pioneer work of Konishi et al,a new control method is proposed to suppress the trafficcongestion in the coupled map (CM) car-following model under open boundary condition.The influence of the followingcar to the system has been considered.Our method and that presented by Konishi et al.[Phys.Rev.E 60 (1999) 4000]are compared.Although both the methods could suppress the traffic jam,the simulation results show that the temporalbehavior obtained by ours is better than that proposed by the Konishi's et al.The simulation results are consistent withthe theoretical analysis.

A new coupled-map car-following model based on a transportation supernetwork framework

A new car-following model is proposed by considering information from a number of preceding vehicles with intervehicle communication. A supernetwork architecture is first described, which has two layers： a traffic network and a communication network. The two networks interact with and depend on each other. The error dynamic system around the steady state of the model is theoretically analyzed and some nonjam criteria are derived. A simple control signal is added to the model to analyze the criteria of suppressing traffic jams. The corresponding numerical simulations confirm the correctness of the theoretical analysis. Compared with previous studies concerning coupled map models, the controlled model proposed in this paper is more reasonable and also more effective in the sense that it takes into account the formation of traffic congestion.

A control method applied to mixed traffic flow for the coupled-map car-following model

In light of previous work [Phys. Rev. E 60 4000 （1999）], a modified coupled-map car-following model is proposed by considering the headways of two successive vehicles in front of a considered vehicle described by the optimal velocity function. The non-jam conditions are given on the basis of control theory. Through simulation, we find that our model can exhibit a better effect as p = 0.65, which is a parameter in the optimal velocity function. The control scheme, which was proposed by Zhao and Gao, is introduced into the modified model and the feedback gain range is determined. In addition, a modified control method is applied to a mixed traffic system that consists of two types of vehicle. The range of gains is also obtained by theoretical analysis. Comparisons between our method and that of Zhao and Gao are carried out, and the corresponding numerical simulation results demonstrate that the temporal behavior of traffic flow obtained using our method is better than that proposed by Zhao and Gao in mixed traffic systems.

Control Chaos of a Unidirectionally Traffic Coupled Map Lattice Model

Spatiotemporal chaos is studied by using the unidirectional traffic coupled lattice model with hyperbolic tangent local map. The coupled map lattice (CML) model can simulate the complex traffic flow phenomenon which is similar to the traditional traffic flow model. The nonlinear feedback method is used to study the control of the chaotic system of the unidirectionally traffic coupled map lattice model. The stability of spatiotemporal chaos in the coupled map lattice is realized. The results of numerical simulation show that there is a relationship between control results and control parameters when controlling spatiotemporal chaos to a uniform stable state in a certain phase space compression parameter region.

基于MapleSim-MATLAB双向耦合技术的液压支架孪生体构建

为解决目前综采工作面存在难以全面掌握装备运行状态监测的问题,以液压支架孪生体的建模为切入点,提出基于MapleSim-MATLAB双向耦合技术的孪生体构建,仿真显示了液压支架升架运动过程中零部件的相对运动及装配关系,并通过实验证明孪生体和物理体交互效果良好。结果表明:以液压支架连杆和底座倾角为例,物理体与孪生体位姿误差率不超过3‰,其拟合度接近1,孪生体和物理体的相互映射,证明该方法能够完成对设备位姿的监测。

基于态势感知的配电网空间负荷预测系统

针对动态地区配电网空间负荷优化预测问题,设计了一种基于实时自控态势感知的配电网空间负荷预测系统。首先构建配电网空间负荷预测目标决策要素经验池;然后利用深度长短期神经网络对配电网历史运行数据集进行处理,实现配电网实时自控态势感知;最后利用深度确定性策略梯度算法构建空间负荷预测与目标决策要素经验池之间的耦合模型,实现配电网空间负荷高效精准预测。对模型展开了实际算例分析,多类型配网供电区域场景下配电网空间负荷预测精度达到91.03%,多类型配网供电区域场景下配电网空间负荷预测效率提高了23.71%。

Real-time flood forecast and flood alert map over the Huaihe River Basin in China using a coupled hydro-meteorological modeling system

A coupled hydro-meteorological modeling system is established for real-time flood forecast and flood alert over the Huaihe River Basin in China. The system consists of the mesoscale atmospheric model MC2 (Canadian Mesoscale Compressible Community) that is one-way coupled to the Chinese Xinanjiang distributed hydrological model, a grid-based flow routing model, and a module for acquiring real-time gauge precipitation. The system had been successfully tested in a hindcast mode using 1998 and 2003 flood cases in the basin, and has been running daily in a real-time mode for the summers of 2005 and 2006 over the Wangjiaba sub-basin of the Huaihe River Basin. The MC2 precipitation combined with gauge values is used to drive the Xinanjiang model for hydrograph prediction and production of flood alert map. The performance of the system is illustrated through an examination of real-time flood forecasts for the severe flood case of July 4―15, 2005 over the sub-basin, which was the first and largest flood event encountered to date. The 96-h forecasts of MC2 precipitation are first evaluated using observations from 41 rain gauges over the sub-basin. The forecast hydrograph is then validated with observations at the Wangjiaba outlet of the sub-basin. MC2 precipitation generally compares well with gauge values. The flood peak was predicted well in both timing and intensity in the 96-hour forecast using the combined gauge-MC2 precipitation. The real-time flood alert map can spatially display the propagation of forecast floods over the sub-basin. Our forecast hydrograph was used as opera-tional guidance by the Bureau of Hydrograph, Ministry of Water Resources. Such guidance has been proven very useful for the Office of State Flood Control and Drought Relief Headquarters in operational decision making for flood management. The encouraging results demonstrate the potential of using mesoscale atmospheric model precipitation for real-time flood forecast, which can result in a longer lead time compared to traditional methods.

Logistic Map三维耦合格子模型模拟环带球晶

应用Logistic map三维耦合格子模型对环带球晶进行了模拟.利用数值计算的方法预测了与实验中环带球晶形貌一致的图案.对于本体体系,环带球晶形貌的带宽随Logistic map中可调参量μ的增大而变窄,随耦合模型中的扩散项系数ε的增大而变宽;对薄膜体系,环带球晶形貌的带宽随格子厚度的增加而变宽,模拟结果与实验结果一致.同时,还给出了螺旋状环带结构在三维空间中的形貌.

数字孪生连接交互理论与关键技术

数字孪生作为实现信息物理融合的重要使能技术,备受各行各业广泛关注。基于虚实交互和数模驱动,数字孪生能满足仿真(以虚映实)、控制(以虚控实)、预测(以虚预实)、优化(以虚优实)等应用服务需求,其中连接与交互是实现数字孪生动态运行和虚实空间高效融合的核心关键。针对数字孪生连接交互如何理解与实现的问题,首先从内外两层阐述了数字孪生连接交互内涵,进而提出“准确—实时—一致—安全—可靠”连接交互准则。在此基础上,从“感知—通信—映射—联动—融合”五方面探索建立了一套数字孪生连接交互理论体系,分析了数字孪生连接交互关键技术。基于数字孪生连接交互理论与方法研究,结合笔者前期在物理实体、数字孪生模型、数字孪生数据和服务的相关研究工作基础,进一步探究并丰富了数字孪生五维模型理论体系,以期为数字孪生的理论研究和应用落地提供系列理论和方法参考。

基于耦合映像格子模型的半导体股票市场稳定性分析

该文从股票所属板块视角研究了当前中国半导体产业网络的发展现状,将复杂网络理论、超图理论与半导体股票板块相结合,构建了半导体股票板块超网络模型,并利用耦合映像格子模型研究了半导体股票板块超网络抵抗外部干扰的能力。通过分析仿真实验结果得出半导体股票板块超网络在随机攻击下较为鲁棒,超网络较为稳定;在蓄意攻击策略下,半导体股票板块超网络较为脆弱。该文的研究结果对研究半导体产业链的稳定性机理、提高产业链的稳定性等方面提供了一定的理论支持。

基于多源大数据和人口分布视角的青岛市中心城区空间结构研究

以青岛市中心城区为例,基于动态的百度热力图和静态的POI数据,借助ArcGIS技术平台,采用栅格计算、核密度分析、耦合协调模型等方法,探究时空两个维度下人群集聚度、集聚位置、活动重心、与POI分布的耦合关系以及城市公共中心等特征。结果表明:工作日人群活动在时空上均受制于通勤节奏,高热力持续时间久;休息日在出行时间上存在滞后特征,空间位置主要集中在商业综合体;人口活动重心迁移在休息日时呈逆时针环形轨迹特征,工作日时轨迹范围更广,反映出就业和商业重心位于居住重心的东北方向;青岛市中心城区人口聚集与POI密度耦合协调关系良好,空间分布上具有“大集聚、小分散”的城市中心体系,存在各级中心发展不平衡、一强多弱等现象。

我国双向投资耦合协调的时空特征及其影响因素

基于我国30个省2008—2021年双向投资存量数据,测度了双向投资耦合协调值以及分析了耦合协调的时空特征,并构建面板Tobit模型考察了推动双向投资协调发展的影响因素。结果表明:双向投资耦合协调值呈逐年上升趋势,在空间上呈现“东部沿海高内陆低”的分布特征;经济规模、对外开放度、技术创新等因素对双向投资协调发展具有显著的促进作用,交通基础设施因素则为负向影响,技术创新和产业结构等因素在“一带一路”沿线重点省份和非重点省份样本中存在明显的异质性影响。

基于耦合映象模型的交通流混沌现象分析

针对交通流耦合映象模型中出现的混沌现象,利用Matlab程序产生交通流时间序列,仿真研究了交通流车队中前后车辆之间车头间距的变化过程,并在此基础上讨论了参数变化对交通流运动状态的影响。结果表明,在该模型产生的交通流中,系统由于参数变化沿着Pomeau-Manne-ville途径走向混沌,从而验证了混沌现象在交通系统中确实存在。

基于三维混沌猫映射的数字图像加密算法

提出了一种新的基于3维混沌猫映射的图像加密方法。该方法采用改进的3维混沌猫映射来提高加密的置乱程度,并把耦合映像格子模型(Coupled map lattice,CML)映射引入加密的扩散过程,明显提高了加密系统的初始敏感性和安全性。仿真结果表明,该方法具有足够大的密钥空间和足够高的安全性,不仅能抵抗差分攻击、选择明文攻击、统计攻击等,而且取得了复杂度和速度的良好折中。

耦合多学科设计系统中参数映射方法

正确地辨识和有效地管理多学科设计模型之间的耦合关系是实现复杂产品多学科设计优化的基础。针对复杂产品研制需求,采用集合概念建立了多学科耦合关系的概念模型。然后,采用面向对象方法实现了耦合多学科设计模型(系统)的参数辨识和表达,并且通过文件解析方法自动关联多学科模型求解器(设计系统)间的输入输出参数。此参数映射方法在参数层次上控制多学科设计数据生成、获取、转换、存储和计算过程,实现了多学科异构数据源互操作。此参数映射方法可以支持耦合学科模型求解器集成,并且支持多学科计算进程的协同调度。此参数映射方法应用于航空装备研制,显著提高了设计效率和设计质量。

基于多重生态系统服务能力指数的生态空间优先级识别

快速城市化地区空间极为有限,识别具有关键景观生态功能的生态源及其保护优先次序,对提升区域多重生态系统服务水平和可持续发展有重要意义.通过构建的耦合模型,评价了生态空间的多重生态系统服务能力指数;基于该指数进行的聚类分析结果将研究区域的生态空间划分为6个优先级.优先级越高表明它的功能重要性越大,维持或提升服务的难度越小,该生态空间越应首先被识别为重要生态源纳入生态网络.这一基于多重生态系统服务能力指数识别生态空间优先级的方法,为其分级管理提供了明确、可重复的方法框架及有用的规划参考信息.