TIME DISCONTINUOUS GALERKIN FINITE ELEMENT METHOD FOR DYNAMIC ANALYSES IN SATURATED PORO-ELASTO-PLASTIC MEDIUM

A time-discontinuous Galerkin finite element method for dynamic analyses in saturated poro-elasto-plastic medium is proposed.As compared with the existing discontinuous Galerkin finite element methods,the distinct feature of the proposed method is that the continuity of the displacement vector at each discrete time instant is automatically ensured,whereas the discontinuity of the velocity vector at the discrete time levels still remains.The computational cost is then obviously reduced, particularly,for material non-linear problems.Both the implicit and explicit algorithms to solve the derived formulations for material non-linear problems are developed.Numerical results show a good performance of the present method in eliminating spurious numerical oscillations and providing with much more accurate solutions over the traditional Galerkin finite element method using the Newmark algorithm in the time domain.

LÉVY AREA ANALYSIS AND PARAMETER ESTIMATION FOR FOU PROCESSES VIA NON-GEOMETRIC ROUGH PATH THEORY

This paper addresses the estimation problem of an unknown drift parameter matrix for a fractional Ornstein-Uhlenbeck process in a multi-dimensional setting.To tackle this problem,we propose a novel approach based on rough path theory that allows us to construct pathwise rough path estimators from both continuous and discrete observations of a single path.Our approach is particularly suitable for high-frequency data.To formulate the parameter estimators,we introduce a theory of pathwise Itôintegrals with respect to fractional Brownian motion.By establishing the regularity of fractional Ornstein-Uhlenbeck processes and analyzing the long-term behavior of the associated Lévy area processes,we demonstrate that our estimators are strongly consistent and pathwise stable.Our findings offer a new perspective on estimating the drift parameter matrix for fractional Ornstein-Uhlenbeck processes in multi-dimensional settings,and may have practical implications for fields including finance,economics,and engineering.

Three Dimensions of Cultivating New Generations: Value Implication, Scientific Connotation, and Cultivation Path

The new generation of the times is the latest requirement for young people in the new era,and it is the latest training goal for young people put forward by the Party and the country in the face of the second centennial goal.At the 19th National Congress,it was put forward by the country that the concept of“new generation of the times”for the first time,indicating the training direction and theoretical guidance for the new generation of the times.The new age requires young people to have firm ideals and beliefs,excellent skills,and a great spirit of responsibility.The proposition of cultivating a new generation of the times is a deep exploration and summary of Marx’s theory of“all-round human development,”Lenin’s youth view and the education view of excellent traditional Chinese culture,and the proposition needs to strengthen the leadership of the Party,give play to the leading role of socialist core values,and the youth themselves should actively act to realize the transformation of theoretical and practical results.

Weighted Time-Based Global Hierarchical Path Planning in Dynamic Environment

A weighted time-based global hierarchical path planning method is proposed to obtain the global optimal path from the starting point to the destination with time optimal control. First, the grid-or graph-based modeling is performed and the environment is divided into a set of grids or nodes. Then two time-based features of time interval and time cost are presented. The time intervals for each grid are built, during each interval the condition of the grid remains stable, and a time cost of passing through the grid is defined and assigned to each interval. Furthermore, the weight is introduced for taking both time and distance into consideration, and thus a sequence of multiscale paths with total time cost can be achieved. Experimental results show that the proposed method can handle the complex dynamic environment, obtain the global time optimal path and has the potential to be applied to the autonomous robot navigation and traffic environment.

Investigating path loss characteristics of UWB signals in vacancy indoor environment based on time-domain technique

The path loss analysis model based on 5 rays in vacancy indoor environment is proposed. The relationship between multipath overlapping and the path loss is analyzed mathematically. Time-domain technique is introduced to compute reflection coefficient in a very short time interval. A 5 rays path loss calculation method, which is satisfactory accurate, is developed. 5 typical environments are involved to analyze and generalize the common path loss characteristics in vacancy indoor environment. The simulation result shows that the path loss can be characterized as 3 zones with different path loss exponent as distance between transmitter and receiver increasing.

Application of A* Algorithm for Real-time Path Re-planning of an Unmanned Surface Vehicle Avoiding Underwater Obstacles

This paper describes path re-planning techniques and underwater obstacle avoidance for unmanned surface vehicle(USV) based on multi-beam forward looking sonar(FLS). Near-optimal paths in static and dynamic environments with underwater obstacles are computed using a numerical solution procedure based on an A* algorithm. The USV is modeled with a circular shape in 2 degrees of freedom(surge and yaw). In this paper, two-dimensional(2-D) underwater obstacle avoidance and the robust real-time path re-planning technique for actual USV using multi-beam FLS are developed. Our real-time path re-planning algorithm has been tested to regenerate the optimal path for several updated frames in the field of view of the sonar with a proper update frequency of the FLS. The performance of the proposed method was verified through simulations, and sea experiments. For simulations, the USV model can avoid both a single stationary obstacle, multiple stationary obstacles and moving obstacles with the near-optimal trajectory that are performed both in the vehicle and the world reference frame. For sea experiments, the proposed method for an underwater obstacle avoidance system is implemented with a USV test platform. The actual USV is automatically controlled and succeeded in its real-time avoidance against the stationary undersea obstacle in the field of view of the FLS together with the Global Positioning System(GPS) of the USV.

The Algorithm of the Time-Dependent Shortest Path Problem with Time Windows

In this paper, we present a new algorithm of the time-dependent shortest path problem with time windows. Give a directed graph , where V is a set of nodes, E is a set of edges with a non-negative transit-time function . For each node , a time window ?within which the node may be visited and ?, is non-negative of the service and leaving time of the node. A source node s, a destination node d and a departure time?t0, the time-dependent shortest path problem with time windows asks to find an s, d-path that leaves a source node s at a departure time t0;and minimizes the total arrival time at a destination node d. This formulation generalizes the classical shortest path problem in which ce are constants. Our algorithm of the time windows gave the generalization of the ALT algorithm and A* algorithm for the classical problem according to Goldberg and Harrelson [1], Dreyfus [2] and Hart et al. [3].

Cooperative path planning for multi-AUV in time-varying ocean flows

For low-speed underwater vehicles, the ocean currents has a great influence on them, and the changes in ocean currents is complex and continuous, thus whose impact must be taken into consideration in the path planning. There are still lack of authoritative indicator and method for the cooperating path planning. The calculation of the voyage time is a difficult problem in the time-varying ocean, for the existing methods of the cooperating path planning, the computation time will increase exponentially as the autonomous underwater vehicle（AUV） counts increase, rendering them unfeasible. A collaborative path planning method is presehted for multi-AUV under the influence of time-varying ocean currents based on the dynamic programming algorithm. Each AUV cooperates with the one who has the longest estimated time of sailing, enabling the arrays of AUV to get their common goal in the shortest time with minimum timedifference. At the same time, they could avoid the obstacles along the way to the target. Simulation results show that the proposed method has a promising applicability.

Optimal Path Finding Method Study Based on Stochastic Travel Time

Finding optimal path in a given network is an important content of intelligent transportation information service. Static shortest path has been studied widely and many efficient searching methods have been developed, for example Dijkstra’s algorithm, Floyd-Warshall, Bellman-Ford, A* et al. However, practical travel time is not a constant value but a stochastic value. How to take full use of the stochastic character to find the shortest path is a significant problem. In this paper, GPS floating car is used to detect road section’s travel time. The probability distribution of travel time is estimated according to Bayes estimation method. The combined probability distribution of a feasible route is calculated according to probability operation. The objective function is to find the route that has the biggest probability to arrive for desired time thresholds. Improved Genetic Algorithm is used to calculate the optimal path. The efficiency of the proposed method is illustrated with a practical example.

Accurate Calculation of Equilibrium Reduced Density Matrix for the System-Bath Model:a Multilayer Multiconfiguration Time-Dependent Hartree Approach and its Comparison to a Multi-Electronic-State Path Integral Molecular Dynamics Approach

An efficient and accurate method for computing the equilibriurn reduced density matrix is presented for treating open quantum systems characterized by the systern-bath model. The method employs the rnultilayer nmlticonfiguration tirne-dependent Hartree theory for imag- inary time propagation and an importance sampling procedure for calculating the quantum mechanical trace. The method is applied to the spin-boson Harniltonian, which leads to ac- curate results in agreement with those produced by the rnulti-electronic-state path integral molecular dynamics method.

Travel path selection based on Nested Logit model And time value calculation

This paper introduces the theory of utility maximization ofNested Logit model,the establishment of selective limbs and its probability expressions;the basic calculation formula of time value. Investigate the travel routes and travel mode choices of residents from Suzhou to Shanghai,consider different impact variables in the survey,and divide their travel lines into two travel days on weekdays due to commuting to Shanghai, and free travel to Shanghai on weekdays.The data of the survey were analyzed and analyzed,and the parameters of the established Nested Logit model were calibrated by ST AT A software.The selection model and time value of the travel route and travel mode of residents under different scenarios and different influence variables were obtained Analyze.

Real-time accurate hand path tracking and joint trajectory planning for industrial robots(Ⅰ)

Previously, researchers raised the accuracy for a robot′s hand to track a specified path in Car-tesian space mainly through increasing the number of knots on the path and the number of the path′s segments, which results in the heavier online computational burden for the robot controller. Aiming at overcoming this drawback, the authors propose a new kind of real-time accurate hand path tracking and joint trajectory planning method. Through selecting some extra knots on the specified hand path by a certain rule and introducing a sinusoidal function to the joint displacement equation of each segment, this method can greatly raise the path tracking accuracy of robot′s hand and does not change the number of the path′s segments. It also does not increase markedly the computational burden of robot controller. The result of simulation indicates that this method is very effective, and has important value in increasing the application of industrial robots.

Nearly time-optimal paths for a ground vehicle

It is well known that the sufficient family of time-optimal paths for both Dubins' as well as Reeds-Shepp' s car models consist of the concatenation of circular arcs with maximum curvature and straight line segments, all tangentially connected. These time-optimal solutions suffer from some drawbacks. Their discontinuous curvature profile, together with the wear and impairment on the control equipment that the bang-bang solutions induce, calls for ' smoother' and more supple reference paths to follow. Avoiding the bang-bang solutions also raises the robustness with respect to any possible uncertainties. In this paper, our main tool for generating these “nearly time-optimal” , but nevertheless continuous-curvature paths, is to use the Pontryagin Maximum Principle (PMP) and make an appropriate and cunning choice of the Lagrangian function. Despite some rewarding simulation results, this concept turns out to be numerically divergent at some instances. Upon a more careful investigation, it can be concluded that the problem at hand is nearly singular. This is seen by applying the PMP to Dubins car and studying the corresponding two point boundary value problem, which turn out to be singular. Realizing this, one is able to contradict the widespread belief that all the information about the motion of a mobile platform lies in the initial values of the auxiliary variables associated with the PMP. Keywords Time-optimal paths - Motion planning - Optimal control - Pontryagin maximum principle - UGV

Real-time accurate hand path tracking and joint trajectory planning for industrial robots(Ⅱ)

Previously, researchers raised the accuracy for a robot′s hand to track a specified path in Cartesian space mainly through increasing the number of knots on the path and the segments of the path. But, this method resulted in the heavier on line computational burden for the robot controller. In this paper, aiming at this drawback, the authors propose a new kind of real time accurate hand path tracking and joint trajectory planning method for robots. Through selecting some extra knots on the specified hand path by a certain rule, which enables the number of knots on each segment to increase from two to four, and through introducing a sinusoidal function and a cosinoidal function to the joint displacement equation of each segment, this method can raise the path tracking accuracy of robot′s hand greatly but does not increase the computational burden of robot controller markedly.

网络文明建设的时代语境、重要特征和实现路径

网络文明是伴随人类进入互联网时代而产生的一种新的文明形式,是人类文明的重要组成部分和重要标志,是社会发展进步的重要体现。加强网络文明建设是实施文化强国和网络强国战略的重要内容。当前,纷繁复杂的国际话语格局、风谲云诡的社会思潮持续威胁我国网络文明建设进程。基于人类文明新形态的时代语境,网络文明建设不仅是社会主义精神文明建设的现实需要,更是推进网络强国战略向纵深发展的重要抓手。网络文明建设应深刻把握党性与人民性统一的价值特征、技术驱动性与发展融合性统一的发展特征、共建性与共享性统一的实践特征和系统性与前瞻性统一的战略特征。为了高质量建设网络文明,须从顶层设计优化、内容生态建设、网络道德建设、网络法治建设和聚力科技赋能五个维度精准把握,坚持制度引领、政治导向、以德促管、依法治网和强化智治支撑,凝聚强大发展合力,构筑积极健康、向上向善的网络文化,为中国式现代化提供风清气正的网络空间与健康和谐的网络生态。

基于改进A^(*)算法的多AGV路径规划及避障研究

针对多自动导引运输车(automated guided vehicle,AGV)路径规划与避障问题,考虑AGV行驶中启、制动速度与转弯角度对行驶时间的影响,根据不同冲突类型制定避障策略,以所有AGV行驶总时间最短为目标,建立多AGV路径规划与避障模型,并设计改进A^(*)算法进行求解。对两组数量不同的多AGV进行路径规划与避障仿真,结果表明:相较于一般A^(*)算法,基于改进A^(*)算法的多AGV路径规划及避障总时间优化率分别为10.0%和10.5%,总路径长度优化率分别为7.1%和7.8%。与其他改进智能算法的进一步比较证实,改进A^(*)算法在缩短路径规划用时和路径长度方面具有明显优势。本文提出的改进A^(*)算法可高效地规划出多AGV运行的无碰撞路径,其改进思路也贴切反映了AGV的实际运行工况。

大运河沿线省市文旅商产业融合发展研究——基于耦合协调、时空演进与发展路径分析

推动大运河沿线省市文旅商产业融合和高质量发展,是有效衔接国家重大发展战略的重要抓手。通过构建文旅商产业评价指标体系,测算大运河沿线省市2012-2020年文旅商产业耦合协调度,分析空间演化特征和影响路径。研究发现:研究期内大运河沿线省市文旅商融合水平整体呈现出逐年上升趋势;文旅商融合水平不同,且具有空间集聚性;在政策保障基础上及文旅商相关因素影响下,文旅商产业通过交叉、渗透和重组,从而实现产业协同发展形成文旅商产业综合体。因此,应采取差异化文旅商融合发展策略,以区域协同发展为基础,以大运河文化带建设为抓手,进一步推动大运河沿线省市形成全域统筹、区域协同的文旅商融合发展格局,实现大运河沿线省市经济社会文化高质量发展。

新时代我国民族传统体育文化的时代价值、现实挑战与行动路径研究

文章运用文献资料法和逻辑分析法等研究方法,对新时代我国民族传统体育文化进行研究。研究认为:助力实施体育强国战略,促进国际化交流与合作,铸牢中华民族共同体意识,提升人民群众幸福感是新时代赋予民族传统体育文化的时代价值;民族传统体育文化同时也面临生存土壤流失、项目参与度不高、文化内涵失真、传承后继乏人等诸多现实挑战,严重阻碍了自身价值的发挥。建议:面对现实挑战,倡导民族传统体育全民健身化;拓展民族传统体育文化传承新路径;加快民族传统体育文化产业融合发展;促进民族传统体育文化国际交流与传播,体现新时代民族传统体育文化时代价值。

城市中心区轨道交通站点步行接驳路径特征及优化

轨道交通站点步行接驳路径特征研究,对提升轨道交通承担率具有重要意义。基于百度时空大数据API,运用空间分析法、情景模拟法、视觉语义分割法,以天津市营口道站点为例,构建城市中心区轨道交通站点步行接驳路径特征分析方法,挖掘步行接驳路径特征并揭示成因,提出针对性的优化对策。研究表明,目标站点步行接驳效率南部高于北部,具体表现在路段重复率分布均匀度南部大于北部,差异路径分布数量北部多于南部,超过3/4路径的非直线系数偏高;除站点周边区域外,接驳路径品质西北部优于东南部,具体表现在西北部视觉出行环境建设最优,区域整体设施服务水平良好。根据步行接驳路径特征,提出路网结构调整、道路断面优化、出入口调整、绿化品质提升的优化对策。

Promote the All-round Development of China's Human Right Cause in the New Era——Summary of the Symposium on “Deeply Studying and Implementing the Spirit of the 20th CPC National Congress and Adhering to the Chinese Path of Human Rights Development”

On November 8, 2022, the symposium on “Deeply Studying and Implementing the Spirit of the 20thCPC National Congress and Adhering to the Chinese Path of Human Rights Development” was held by the China Society for Human Rights Studies in Beijing. Focusing on “the leadership of the CPC and human rights development”, “adapting Marxism to the Chinese context and the needs of our times and human rights theories in contemporary China”, “the Chinese path to modernization and the new form of human rights civilization”, “Chinese human rights solutions and global human rights governance”, “making a better China’s story of advancing human rights and constructing human rights discourse system”, and other topics, the participants reached broad consensus after discussion, and the symposium achieved fruitful results.