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61.
This work introduces a novel route reservation architecture to manage road traffic within an urban area. The developed routing architecture decomposes the road infrastructure into slots in the spatial and temporal domains and for every vehicle, it makes the appropriate route reservations to avoid traffic congestion while minimizing the traveling time. Under this architecture, any road segment is admissible to be traversed only during time-slots when the accumulated reservations do not exceed its critical density. A road-side unit keeps track of all reservations which are subsequently used to solve the routing problem for each vehicle. Through this routing mechanism, vehicles can either be delayed at their origin or are routed through longer but non-congested routes such that their traveling time is minimized. In this work, the proposed architecture is presented and the resulting route reservation problem is mathematically formulated. Through a complexity analysis of the routing problem, it is shown that for certain cases, the problem reduces to an NP-complete problem. A heuristic solution to the problem is also proposed and is used to conduct realistic simulations across a particular region of the San Francisco area, demonstrating the promising gains of the proposed solution to alleviate traffic congestion. 相似文献
62.
为解决船舶避碰自动化领域的多船智能避碰决策问题, 建立了多层次多目标重点避让船模糊优选模型。分析了碰撞危险度和避让难易程度对重点避让船决策的影响, 通过划分相互关联的有序层次结构使问题条理化, 利用多目标模糊优选理论, 建立了相应的模糊优选模型, 以低层次的输出作为高层次的输入, 对每一层次的单元系统进行优化计算, 利用相对优属度向量进行排序, 确定重点避让船。模拟计算了一艘船同时和7艘目标船相遇时重点避让船相对优属度向量, 按相对优属度越大排序越前的原则确定目标船3为重点避让船, 决策结果正确, 该模型可行。 相似文献
63.
《中国舰船研究》2023,(1):29-42and51
The underwater glider (UG) is a new type of underwater vehicle driven by buoyancy, which has the advantages of low energy consumption, high efficiency, long-endurance, low cost, reusability and so on. The UG can also meet the needs of long-term and large-scale ocean observation and exploration. As an observation platform, the UG needs to carry out path planning and correction continuously in the early stages and during missions in order to better serve the requirements of ocean observation and exploration. First, this paper summarizes the relevant literatures on path planning research methods for UG in recent years. UG path planning algorithms are mainly divided into three categories: traditional algorithms, intelligent optimization algorithms and multi-algorithm fusions. Combined with practical application, the performance of different path planning algorithms is compared. The key technologies of UG path planning, such as environment reconstruction, environment perception, intelligent decision-making and underwater positioning, are then summarized. Finally, the development direction of UG multi-algorithm integration, multi-glider cooperation, multi-dimensional integration of spatiotemporal constraints and high-precision in complex and unsteady environments are prospected. © 2023 The Author(s).
64.
《智能交通系统杂志
》2012,16(2):93-125
》2012,16(2):93-125
ABSTRACT This paper describes the complex issues associated with proactive prediction of the safety impact of in-vehicle ITS and discusses two techniques for potentially successfully estimating such impacts. Specifically, indirect measurement of safety via promising surrogates, using near crashes and driver errors, as a means to predict crash rate is discussed. This discussion addresses the distinction between near misses and driver errors, and methods for data collection and analysis. The second method discussed is the collection of empirical, instrumented vehicle data for the specific purpose of providing input into models which estimate safety impacts. This concept, the collection of basic driver behavior and performance data in direct support of providing input to models is discussed by way of example 相似文献
65.
66.
针对船舶避碰决策行为差异,提出一种运用前景理论求取最佳船舶避碰决策方案的优化方法。在分析避碰行为个体差异的基础上,运用前景理论和多指标灰关联决策相结合的方法,构建考虑驾驶员风险态度的船舶避碰方案选择决策优化模型,以船舶碰撞危险度、航程损失和轨迹平稳性作为决策指标,研究在同一会遇场景下驾驶员不同风险态度的最优避碰方案并进行对比分析。研究结果表明:该模型可优化船舶驾驶员在不同风险偏好下的最优避碰方案选择,将前景理论运用到船舶避碰决策优化中是可行且有效的,能为船舶避碰决策和决策拟人化提供支持。 相似文献
67.
Conducting hydrodynamic and physical motion simulation tests using a large-scale self-propelled model under actual wave conditions is an important means for researching environmental adaptability of ships. During the navigation test of the self-propelled model, the complex environment including various port facilities, navigation facilities, and the ships nearby must be considered carefully, because in this dense environment the impact of sea waves and winds on the model is particularly significant. In order to improve the security of the self-propelled model, this paper introduces the Q learning based on reinforcement learning combined with chaotic ideas for the model＇s collision avoidance, in order to improve the reliability of the local path planning. Simulation and sea test results show that this algorithm is a better solution for collision avoidance of the self navigation model under the interference of sea winds and waves with good adaptability. 相似文献
68.
69.
制动过程主要由制动前的反应过程以及制动后的减速过程组成.研究制动后避撞行为对于理解驾驶人的避撞行为、建立制动曲线模型等有着重要作用.利用配有8自由度运动系统的高仿真驾驶模拟器,研究了驾驶人在不同前车减速度(0.3,0.5,0.75g)和不同车头时距(1.5,2.5 s)的制动后制动踏板操作行为.利用ANOVA模型分别比较了驾驶人制动后制动踏板操作行为参数的.差异.结果表明,踩踏板速率随着制动时车头时距的减少而增加,并且随着前车减速度的减少而减少;新手驾驶人的踩踏板速率普遍大于经验驾驶人;相比于前车速度的改变,驾驶人对制动时车头时距的变化更加敏感. 相似文献
70.
Barbara Santer 《Journal of Marine Systems》1998,15(1-4)
Freshwater copepods live in habitats characterized by a high degree of instability. To survive occasional deterioration of their environment copepods have evolved adaptive mechanisms like dormancy or migration in order to avoid lethal conditions and to synchronize growth and reproduction with favourable abiotic and biotic conditions. Typical life cycles of harpacticoid, calanoid and cyclopoid copepods are presented to show strategies that have evolved to survive threatening environmental conditions. 相似文献