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NONEMPTY INTERSECTION THEOREMS AND SYSTEM OF GENERALIZED VECTOR EQUILIBRIUM PROBLEMS IN PRODUCT G-CONVEX SPACES 被引量:3
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作者 丁协平 《应用数学和力学》 EI CSCD 北大核心 2004年第6期563-571,共9页
By using an existence theorems of maximal elements for a family of set-valued mappings in G-convex spaces due to the author, some new nonempty intersection theorems for a family of set-valued mappings were established... By using an existence theorems of maximal elements for a family of set-valued mappings in G-convex spaces due to the author, some new nonempty intersection theorems for a family of set-valued mappings were established in noncompact product G-convex spaces. As applications, some equilibrium existence theorems for a system of generalized vector equilibrium problems were proved in noncompact product G-convex spaces. These theorems unify, improve and generalize some important known results in literature. 展开更多
关键词 集值映象组 非空交定理 广义矢量平衡问题组 乘积G凸空间
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NONEMPTY INTERSECTION THEOREMS AND SYSTEM OF GENERALIZED VECTOR EQUILIBRIUM PROBLEMS IN PRODUCT G-CONVEX SPACES 被引量:4
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作者 DINGXie-ping 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2004年第6期618-626,共9页
By using an existence theorems of maximal elements for a family of set-valued mappings in G-convex spaces due to the author, some new nonempty intersection theorems for a family of set-valued mappings were established... By using an existence theorems of maximal elements for a family of set-valued mappings in G-convex spaces due to the author, some new nonempty intersection theorems for a family of set-valued mappings were established in noncompact product G-convex spaces. As applications, some equilibrium existence theorems for a system of generalized vector equilibrium problems were proved in noncompact product G-convex spaces. These theorems unify, improve and generalize some important known results in literature. 展开更多
关键词 family of set-valued mapping nonempty intersection theorem system of generalized vector equilibrium problem product G-convex space
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A New Browder Fixed Point Theorem in Noncompact Hyperconvex Metric Spaces and Its Applications to Section Questions and Intersection Questions 被引量:3
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作者 WEN Kai-ting 《Chinese Quarterly Journal of Mathematics》 CSCD 2009年第1期112-116,共5页
In this paper, a new Browder fixed point theorem is established in the noncompact sub-admissible subsets of noncompact hyperconvex metric spaces. As application, a Ky Fan section theorem and an intersection theorem ar... In this paper, a new Browder fixed point theorem is established in the noncompact sub-admissible subsets of noncompact hyperconvex metric spaces. As application, a Ky Fan section theorem and an intersection theorem are obtained. 展开更多
关键词 hyperconvex metric space fixed point sub-admissible set noncompact measure SECTION intersection
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Analytical method of minimum spacing of signalized intersections on bidirectional two-lane highways
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作者 马永锋 袁黎 张文波 《Journal of Southeast University(English Edition)》 EI CAS 2015年第4期547-552,共6页
In order to improve the smoothness of traffic flow on bidirectional two-lane highways, an analytical method is proposed to optimize the minimum spacing of the signalized intersections. The minimum signal spacing is de... In order to improve the smoothness of traffic flow on bidirectional two-lane highways, an analytical method is proposed to optimize the minimum spacing of the signalized intersections. The minimum signal spacing is determined by two parts, including the necessary distance for stabilizing the traffic flow after it passes through the signalized intersections and the length of the upstream functional area of intersection. For the former, based on the platoon dispersion theory, the stable distance determination problem of traffic flow is studied and a model of dispersion degrees varying with the distance from the upstream intersection is presented, in which the time headway is intended to yield the shifted negative exponential distribution. The parameters of the model for medal and collector highways are estimated respectively based on the field data. Then, the section at which the slope of dispersion degree curve equals -0.1 is regarded as the beginning of the dispersion stable state. The length of the intersection upstream functional area is determined by three parts, including the distance traveled during perception-reaction time, the distance traveled while a driver decelerates to a stop, and the queue storage length. Based on the above procedures, the minimum signal spacing of each highway category is proposed. 展开更多
关键词 HIGHWAY signalized intersection SPACING platoon dispersion
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QUASI_EQUILIBRIUM PROBLEMS IN NONCOMPACT GENERALIZED CONVEX SPACES 被引量:3
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作者 丁协平 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2000年第6期637-644,共8页
By applying a new fixed point theorem due to the author, some new equilibrium existence theorems of quasi-equilibrium problems are proved in noncompact generalized convex spaces. These theorems improve and generalize ... By applying a new fixed point theorem due to the author, some new equilibrium existence theorems of quasi-equilibrium problems are proved in noncompact generalized convex spaces. These theorems improve and generalize a number of important known results in recent literature. 展开更多
关键词 fixed point quasi-equilibrium problem compactly local intersection property generalized convex space
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NEW COLLECTIVELY FIXED POINT THEOREMS AND APPLICATIONS IN G-CONVEX SPACES
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作者 丁协平 Park Jong-yeoul 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 2002年第11期1237-1249,共13页
By applying the technique of continuous partition of unity and Tychonoff's fixed point theorem,. some new collectively fixed point theorems for a family of set-valued, mappings defined on the product space of nonc... By applying the technique of continuous partition of unity and Tychonoff's fixed point theorem,. some new collectively fixed point theorems for a family of set-valued, mappings defined on the product space of noncompact G-convex spaces are proved. As applications, some nonempty intersetion theorems of Ky Fan type for a family of subsets of the product space of G convex spaces are proved; An existence theorem of solutions for a system of nonlinear inequalities is given in G-convex spaces and some equilibrium existence of abstract economies are also obtained in G convex spaces. Our theorems theorems of improve, unify and generalized many important known results in recent literature. 展开更多
关键词 collectively fixed point nonempty intersection theorem system of inequality abstruct economy generalized convex space
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A Characterization of Complex Projective Spaces by Sections of Line Bundles
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作者 Shuyu Liang Yanan Gao Yicai Zhao 《Advances in Pure Mathematics》 2015年第8期450-453,共4页
Let M be a n-dimensional compact irreducible complex space with a line bundle L. It is shown that if M is completely intersected with respect to L and dimH0(M, L) = n + 1, then M is biholomorphic to a complex projecti... Let M be a n-dimensional compact irreducible complex space with a line bundle L. It is shown that if M is completely intersected with respect to L and dimH0(M, L) = n + 1, then M is biholomorphic to a complex projective space Pn of dimension n. 展开更多
关键词 Complex space PROJECTIVE space LINE BUNDLE COMPLETE intersected
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Analysis of the Impact of Large Constellations on the Space Debris Environment and Countermeasures 被引量:1
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作者 CHEN Chuan YANG Wulin +2 位作者 GONG Zizheng ZHANG Pinliang LI Ming 《Aerospace China》 2020年第2期16-22,共7页
Large constellations have developed rapidly in recent years because of their unique advantages, but they will inevitably have a major negative impact on the space debris environment, leading to its deterioration. The ... Large constellations have developed rapidly in recent years because of their unique advantages, but they will inevitably have a major negative impact on the space debris environment, leading to its deterioration. The key to mitigate the impact is the success rate and duration of the post-mission disposal(PMD) process. Aiming at solving this problem, this paper further studies the impact of large constellations on other space assets under different PMD strategies through simulation, and proposes corresponding strategies and suggestions for mitigation.According to One Web’s large constellation launch plan, the dangerous intersection of the large constellation with existing space assets at different stages of the constellations life cycle is calculated by simulation. Based on this, the influence of the large constellation operation on existing space assets at different times and strategies of PMD is analyzed. The conclusion shows that in the PMD stage, large constellations have the greatest impact on existing space assets;the PMD duration and number of satellites performing PMD at the same time are key factors to the degree of negative impact. The faster the PMD is, the less threat it poses to other spacecraft. More results and conclusions are still being analyzed. 展开更多
关键词 large constellations space debris environment long-term environmental evolution impact probability dangerous intersection coping strategies
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A Method of Precision Testing Relative Relation of Space Points and Its Application
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作者 田林亚 李鹏 夏开旺 《Journal of China University of Mining and Technology》 2003年第1期48-51,共4页
In response to the high requirements of industrial precision test, presenting a method of testing relative relation of space points was studied. The spatial-coordinate testing system was established by using high prec... In response to the high requirements of industrial precision test, presenting a method of testing relative relation of space points was studied. The spatial-coordinate testing system was established by using high precision theodolites and horizontal staff. The related test was conducted with the use of the space intersection and the precision was evaluated based on the error of baseline. In the practical application of radar-development base, the relative relation of space points was implemented by using electronic theodolite and horizontal staff, which can be easily operated. Furthermore, it can be conveniently used to test small areas where the instruments are difficult to be installed and for high industrial requirements of precision test. The test results can fully meet the strict industrial requirements. 展开更多
关键词 THEODOLITE horizontal staff testing system space intersection
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Groove modeling and digital simulation for intersecting structures of circular tubes based on coplanarity of vectors
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作者 Chen Changrong Zhou Sunsheng +3 位作者 Lian Guofu Huang Xu Feng Meiyan Gao Xianfeng 《China Welding》 CAS 2022年第2期29-38,共10页
In order to establish the groove model for intersecting structures of circular tubes,mathematical model of the intersecting line is established by the method of analytic geometry,and parametric equations are thus dete... In order to establish the groove model for intersecting structures of circular tubes,mathematical model of the intersecting line is established by the method of analytic geometry,and parametric equations are thus determined.The dihedral angle,groove angle and actual cutting angle for any position of the intersecting line are derived as well.In order to identify groove vectors for two pipes,a new analytical method,i.e.coplanarity of vectors,is further proposed to complete the groove model.The established model is virtually verified by programming and simulation calculation in the MATLAB environment.The results show that groove vectors of intersecting structures simulated by MATLAB are consistent with the theoretical groove model,indicating that the theoretical groove model established in this paper is accurate,and further proves that the proposed coplanarity of vectors for solving groove vectors is correct and feasible.Finally,a graphical user interface(GUI)is developed by MATLAB software to independently realize functions such as model drawing,variable calculation and data output.The research outcome provides a theoretical foundation for the actual welding of circular intersecting structures,and lays an essential basis for weld bead layout and path planning. 展开更多
关键词 method of analytic geometry in space intersecting line mathematical model coplanarity of vectors groove model MATLAB simulation
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考虑行人过街的交叉口综合待驶区一体化模型
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作者 吴先宇 范宏伟 梁衡 《北京交通大学学报》 北大核心 2025年第1期136-147,共12页
为解决传统综合待驶区时空资源利用不够充分,从而导致交叉口人车交通效益损失问题,研究并提出一种考虑行人过街的新型交叉口综合待驶区一体化模型.首先,论述新型综合待驶区的设计形式、控制策略和适用条件.其次,结合车流与行人过街运行... 为解决传统综合待驶区时空资源利用不够充分,从而导致交叉口人车交通效益损失问题,研究并提出一种考虑行人过街的新型交叉口综合待驶区一体化模型.首先,论述新型综合待驶区的设计形式、控制策略和适用条件.其次,结合车流与行人过街运行规律,分别提出车辆和行人过街的延误计算模型.再次,考虑行人过街安全以及人车运行效益,基于控制策略构建最佳时空资源分配模型.最后,使用Vissim仿真软件对模型进行实例验证.研究结果表明:采用新型综合待驶区的优化方案可以将过饱和交叉口优化至非饱和状态,并将各方向车流饱和度降低至0.8以下;关键流向的通行能力相较于现状提升40%以上,交叉口平均停车延误降低50%以上,车均停车次数降低约30%,并且优化效果好于传统的Webster配时方法;相较于传统的综合待驶区,新型综合待驶区及其控制策略新增了预信号处的行人过街相位以及对右转车辆的控制,进一步利用了交叉口内时空资源,在提升交叉口通行能力的同时又为行人过街提供了新的选择. 展开更多
关键词 信号交叉口 综合待驶区 行人过街 时空资源分配
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基于改进深度强化学习的交通信号灯控制
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作者 韦敏 蔡常健 《计算机工程与设计》 北大核心 2025年第3期927-933,共7页
为解决复杂交通情境下传统交通信号灯控制效果有限的问题,提出一种改进的深度强化学习交通信号灯控制方法。将对决网络和双Q学习结合,改进深度强化学习模型结构,缓解算法的高估;设计能提取更丰富交通信息的多特征状态空间,考虑车辆等待... 为解决复杂交通情境下传统交通信号灯控制效果有限的问题,提出一种改进的深度强化学习交通信号灯控制方法。将对决网络和双Q学习结合,改进深度强化学习模型结构,缓解算法的高估;设计能提取更丰富交通信息的多特征状态空间,考虑车辆等待时间和车道最大队列长度的多任务奖励函数,提高城市交叉口的通行效率。实验结果表明,所提方法能够获得更高奖励,在训练场景对比基线方法平均等待时间和平均队列长度均明显降低,平均速度明显提高,测试结果同样验证所提方法更能提高道路通行效率。 展开更多
关键词 深度强化学习 信号灯控制 对决网络 状态空间 奖励函数 城市交叉口 交通工程
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“交通流量管控”的问题分析
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作者 李金秀 王晓童 王浩铭 《时代汽车》 2025年第24期162-165,共4页
以2024年“高教社杯”全国大学生数学建模竞赛E题为背景,建立交通路口的数学模型。随着城市化进程的加快、机动车的快速普及,以及人们活动范围的不断扩大,城市道路交通拥堵问题日渐严重,即使在一些非中心城市,道路交通拥堵问题也成为影... 以2024年“高教社杯”全国大学生数学建模竞赛E题为背景,建立交通路口的数学模型。随着城市化进程的加快、机动车的快速普及,以及人们活动范围的不断扩大,城市道路交通拥堵问题日渐严重,即使在一些非中心城市,道路交通拥堵问题也成为影响地方经济发展和百姓幸福感的一个“痛点”,也是相关部门的棘手难题之一。文章的研究从各交叉路口车流量数据统计分析入手,分析了12个交叉路口的车流量,计算出车流速度,在考虑车型、车道数、安全距离等因素的情况之下,计算出主干道红绿灯时长、黄金周交通拥堵问题、停车位问题等,目的是使交通更优化,游客到达景区游览的感受更好,进而能让景区经济效益最大化。 展开更多
关键词 车流量 车速 交叉路口 停车位
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基于RANSAC和ICP点云优化算法的机器人相贯线免示教自主焊接方法 被引量:1
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作者 熊凡 许燕玲 +3 位作者 王杏华 马晓阳 王强 张华军 《航空制造技术》 北大核心 2025年第20期100-108,共9页
针对航空航天领域中空间曲线焊缝示教再现型机器人焊接效率较低的问题,尤其是复杂的相贯线焊接,提出了一种基于优化后的RANSAC和ICP点云算法的相贯线机器人免示教自主焊接方法。首先基于相贯线理论模型,对采集到的工件点云进行预处理,... 针对航空航天领域中空间曲线焊缝示教再现型机器人焊接效率较低的问题,尤其是复杂的相贯线焊接,提出了一种基于优化后的RANSAC和ICP点云算法的相贯线机器人免示教自主焊接方法。首先基于相贯线理论模型,对采集到的工件点云进行预处理,并采用优化后的RANSAC算法,选取一定数量的点作为样本点拟合曲面,计算所有数据点到柱面的距离,根据预设阈值筛选出落在拟合曲面上的点,通过筛选出的点重新拟合出实际的圆柱面方程。然后通过ICP算法,迭代寻找两个点云之间的最近点对,计算最优的刚性变换,使源点云在目标点云的坐标系下对齐。最后试验验证了所提出的基于优化后的RANSAC和ICP点云优化算法,实现复杂空间曲线的机器人免示教自主焊接。 展开更多
关键词 机器人焊接 自动编程 视觉传感 空间曲线焊缝 相贯线焊接
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基于LSTM-GNN的畸形交叉口自适应信号控制仿真研究 被引量:2
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作者 陈坤 陈亮 +3 位作者 谢济铭 刘丰博 陈泰熊 位路宽 《系统仿真学报》 北大核心 2025年第6期1343-1351,共9页
针对畸形交叉口交通拥堵情况,设计了一种基于深度学习的改进型自适应交通信号控制方案,融合了LSTM与GNN在畸形交叉口的自适应信号控制。LSTM捕捉时间序列交通数据之间的依赖性,GNN构建车道间的空间交互模型。通过整合时间和空间维度的信... 针对畸形交叉口交通拥堵情况,设计了一种基于深度学习的改进型自适应交通信号控制方案,融合了LSTM与GNN在畸形交叉口的自适应信号控制。LSTM捕捉时间序列交通数据之间的依赖性,GNN构建车道间的空间交互模型。通过整合时间和空间维度的信息,该模型能够依据实时交通状况动态调整信号灯的相位时长。结果表明:LSTM-GNN自适应控制方案相比传统固定信号控制提高了约17.3%的整体通过效率。 展开更多
关键词 深度学习 LSTM GNN 交通信号控制 畸形交叉口 自适应控制 交通流优化 时空依赖性
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基于时空结构特性的战斗部检测研究
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作者 方龙 李浩 +2 位作者 王磊 随亚光 张云峰 《兵器装备工程学报》 北大核心 2025年第1期116-121,共6页
为解决外场复杂动态环境下战斗部检测困难且易受干扰的问题,提出一种外场试训条件下基于目标时空结构特性的落区战斗部检测方法,以经济可靠的通用网络高清或工业相机为观测设备,针对其成像特点,结合光流追踪技术,设计了一种基于战斗部... 为解决外场复杂动态环境下战斗部检测困难且易受干扰的问题,提出一种外场试训条件下基于目标时空结构特性的落区战斗部检测方法,以经济可靠的通用网络高清或工业相机为观测设备,针对其成像特点,结合光流追踪技术,设计了一种基于战斗部时空结构特性的远距离、小目标追踪方法,研究结果表明,结合战斗部运动规律光流追踪技术及目标间时空结构特性的轨迹检测算法的战斗部错检率为5%,而传统检测方法错检率高达89.6%,所研究方法有助于实现战斗部的实时精准检测及在试训场地的大规模快速部署应用。 展开更多
关键词 战斗部检测 弹目交会 时空结构特性 光流追踪 轨迹检测
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The Convex-Set Algebra and Intersection Theory on the Toric Riemann–Zariski Space
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作者 Ana María BOTERO 《Acta Mathematica Sinica,English Series》 SCIE CSCD 2022年第3期465-486,共22页
In previous work of the author,a top intersection product of toric b-divisors on a smooth complete toric variety is defined.It is shown that a nef toric b-divisor corresponds to a convex set and that its top inetersec... In previous work of the author,a top intersection product of toric b-divisors on a smooth complete toric variety is defined.It is shown that a nef toric b-divisor corresponds to a convex set and that its top inetersection number equals the volume of this convex set.The goal of this article is to extend this result and define an intersection product of sufficiently positive toric b-classes of arbitrary codimension.For this,we extend the polytope algebra of McMullen to the so called convex-set algebra and we show that it embeds in the toric b-Chow group.In this way,the convex-set algebra can be viewed as a ring for an intersection theory for sufficiently positive toric b-classes.As an application,we show that some Hodge type inequalities are satisfied for the convex set algebra. 展开更多
关键词 Convex geometry intersection theory toric varieties b-Chow groups Riemann–Zariski spaces
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城市道路交叉口慢行空间优化设计
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作者 陈辅光 《工程技术研究》 2025年第20期192-194,共3页
当前我国机动车保有量大幅增加,为提高道路交通运行的协调性和效率,城市道路慢行空间的设计日渐受到关注。但慢行空间中的“车本位”和“人本位”矛盾是慢行空间设计效能的关键影响因素,如何通过合理的优化设计实现城市道路交叉口的慢... 当前我国机动车保有量大幅增加,为提高道路交通运行的协调性和效率,城市道路慢行空间的设计日渐受到关注。但慢行空间中的“车本位”和“人本位”矛盾是慢行空间设计效能的关键影响因素,如何通过合理的优化设计实现城市道路交叉口的慢行一体化,是当前城市道路规划不可忽视的难点。为此,探讨当前城市道路交叉口慢行空间设计难点,提出慢行空间优化设计的可行策略,旨在完善城市道路交叉口的慢行空间规划,保障道路交通的安全性、高效性和流畅性。 展开更多
关键词 城市道路 交叉口 慢行空间优化设计 城市规划
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互通立交出入口匝道与平交口的组合类型及理论间距
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作者 陈东升 梁学荣 +1 位作者 袁英爽 王世伟 《城市道桥与防洪》 2025年第7期37-42,共6页
随着城镇化地区公路功能的不断拓展,城镇化地区一级公路已然成为服务对象齐全、行车速度快、车速离散度大的矛盾集中凸显的公路。为提高城镇化地区一级公路的通行能力,保障运行安全,将一级公路互通立交出入口匝道与平交口按照入口匝道-... 随着城镇化地区公路功能的不断拓展,城镇化地区一级公路已然成为服务对象齐全、行车速度快、车速离散度大的矛盾集中凸显的公路。为提高城镇化地区一级公路的通行能力,保障运行安全,将一级公路互通立交出入口匝道与平交口按照入口匝道-出口道、出口匝道-出口道、入口匝道-进口道、出口匝道-进口道4种类型组合方式进行合理间距研究。研究内容主要为基于基础设施设置和驾驶行为的共同影响对研究对象进行理论距离计算,分别提出了4种组合方式下的理论计算间距推荐值,可为深入探究城镇化地区公路互通立交与平交口的间距提供参考。 展开更多
关键词 城镇化地区公路 出入口匝道 平交口 组合类型 理论间距
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基于VISSIM仿真的互通入口匝道与平交口进口道组合路段运行影响因素分析及间距确定
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作者 袁英爽 王世伟 +1 位作者 陈东升 梁学荣 《城市道桥与防洪》 2025年第7期11-17,22,共8页
随着城镇化地区公路功能的不断发展,城镇化地区一级公路已然成为服务对象齐全、行车速度高、车速离散度大的矛盾集中凸显的公路。为提高城镇化地区一级公路的通行能力以及安全性,以入口匝道与平交口进口道的理论间距计算为基础,进行VIS... 随着城镇化地区公路功能的不断发展,城镇化地区一级公路已然成为服务对象齐全、行车速度高、车速离散度大的矛盾集中凸显的公路。为提高城镇化地区一级公路的通行能力以及安全性,以入口匝道与平交口进口道的理论间距计算为基础,进行VISSIM仿真实验设计。分别针对匝道交通量分布、平交口转向交通量、交通组成、匝道与平交口进口间距4种影响因素进行仿真分析,从车辆运行速度、延误和排队的角度分析入口匝道-平交口进口道各组合类型路段的车辆运行特征,并提出互通入口匝道与平交口进口道间距的设计建议。 展开更多
关键词 城镇化地区一级公路 入口匝道 平交口 运行特征 布设间距
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