A Real-Time Parking Prediction System for Smart Cities

A methodological framework for multiple steps ahead parking availability prediction is presented. Two different types of predictions are provided: the probability of a free space to continue being free in subsequent time intervals, and the short-term parking occupancy prediction in selected regions of an urban road network. The available data come from a wide network of on-street parking sensors in the “smart” city of Santander, Spain. The sensor network is segmented in four different regions, and then survival and neural network models are developed for each region separately. Findings show that the Weibull parametric models best describe the probability of a parking space to continue to be free in the forthcoming time intervals. Moreover, simple genetically optimized multilayer perceptrons accurately predict region parking occupancy rates up to 30 minutes in the future by exploiting 1-minute data. Finally, the real time, Web-based, implementation of the proposed parking prediction availability system is presented.     

RTA48-T型主机气动操纵系统仿真及应用

主机气动操纵系统的主要功能是完成主机的起动、换向和调速。因其包含的气动元器件多,逻辑关系复杂,一旦发生故障,难于判断,因此加强船员对气动操纵系统方面的训练和培训是轮机管理中的一项重点和难点内容。在现有轮机仿真训练系统中,主机气动操纵系统仿真模型为MAN公司的 MC型气动操纵系统,为了扩展现有轮机仿真系统的训练功能,满足不同机型气动操纵系统的训练要求,本文采用逻辑建模方法,同时又考虑到部件的延时特性,建立了瓦锡兰公司的RTA48-T型主机气动操纵系统仿真模型;利用VC++编程软件完成了模型计算;开发了主机气动操纵系统的二维可视化仿真界面;仿真结果表明,模型可以对常见故障进行仿真并与实际现象相吻合。二维界面既能展现实际系统的逻辑关系,又能对延时过程实现可视化动态展示,更好地满足了教学与培训的使用要求。     

三轴燃机动态建模方法与仿真程序开发

燃气轮机动态仿真模型是研究燃机多变量控制理论、进行燃机健康管理等应用的重要基础,有着很强的实用价值。本文给出了一种基于迭代法的三轴燃气轮机设计点、非设计点和瞬态工作点性能计算通用程序的设计方法。仿真结果表明该方法设计的动态模型能较好的模拟燃机在不同工况下的性能变化,具有较好的应用前景。     

铁路BIM工程化实施策略研究

为解决BIM技术在铁路工程应用中的相关问题,如BIM实施目标不明确,BIM专业人员短缺,BIM相关投入与收益不成正比等,从铁路BIM技术应用、基于BIM的工作流程再造、标准BIM合同文本研制、经济效益量化研究、铁路BIM平台研发、铁路BIM实施标准指南编制和铁路BIM培训等7个方面提出了铁路BIM工程化实施策略,并结合...     

一种考虑迟滞的动力电池模型及其参数识别

建立精确的电池模型是实现电池管理策略仿真及验证的前提,是实现对动力电池进行全面、高效、精细化的管理的关键。然而在动力电池充放电过程中出现的电压迟滞现象,严重影响了动力电池的建模精度。文章建立了一种考虑锂离子电池充放电电压迟滞的电池模型,并对其进行了参数识别,可供从事相关锂离子电池状态分析的研究人员作为参考。     

Comparison between a reanalyzed product by 3-dimensional variational assimilation technique and observations in the Ulleung Basin of the East/Japan Sea

Reanalyzed products from a MOM3-based East Sea Regional Ocean Model with a 3-dimentional variational data assimilation module (DA-ESROM), have been compared with the observed hydrographic and current datasets in the Ulleung Basin (UB) of the East/Japan Sea (EJS). Satellite-borne sea surface temperature and sea surface height data, and in-situ temperature profiles have been assimilated into the DA-ESROM. The performance of the DA-ESROM appears to be efficient enough to be used in an operational ocean forecast system.Comparing with the results from Mitchell et al. [Mitchell, D. A., Watts, D. R., Wimbush, M., Teague, W.J., Tracey, K. L., Book, J. W., Chang, K.-I., Suk, M.-S., Yoon, J.-H., 2005a. Upper circulation patterns in the Ulleung Basin. Deep-Sea Res. II, 52, 1617-1638.], the DA-ESROM fairly well simulates the high variability of the Ulleung Warm Eddy and Dok Cold Eddy as well as the branching of the Tsushima Warm Current in the UB. The overall root-mean-square error between 100 m temperature field reproduced by the DA-ESROM and the observed 100-dbar temperature field is 2.1 °C, and the spatially averaged grid-to-grid correlation between the two temperature fields is high with a mean value of 0.79 for the inter-comparison period.The DA-ESROM reproduces the development of strong southward North Korean Cold Current (NKCC) in summer consistent with the observational results, which is thought to be an improvement of the previous numerical models in the EJS. The reanalyzed products show that the NKCC is about 35 km wide, and flows southward along the Korean coast from spring to summer with maximum monthly mean volume transport of about 0.8 Sv in August–September.     

轨道交通工程BIM+GIS云平台微服务架构研究

为解决轨道交通工程BIM+GIS云平台在多站点、多区间、多线路管理中,BIM、GIS数据量大、数据服务庞杂、并发访问量大等问题,研究分析单体服务架构缺陷和微服务架构优势,在制定微服务拆分方式和设计原则的基础上,实现了轨道交通工程BIM+GIS云平台的微服务架构设计.并在大连地铁5号线火梭区间海底盾构隧道施工中进行应用....     

Assessing the impact of cornering losses on the energy consumption of electric city buses

In view of the increasing electrification of public city transport, an accurate energy consumption prediction for Battery Electric Buses (BEBs) is essential. Conventional prediction algorithms do not consider energy losses that occur during turning of the vehicle. This is especially relevant for electric city buses, which have a limited battery capacity and often drive curvy routes.In this paper, the additional energy consumption during steering of a BEB is modeled, measured, and assessed. A nonlinear steady-state cornering model is developed to establish the additional energy losses during cornering. The model includes large steer angles, load transfer, and a Magic Formula tire model. Model results show that both cornering resistance and tire scrub of the rear tires cause additional energy losses during cornering, depending on the corner radius and vehicle velocity.The energy consumption model is validated with full scale vehicle tests and shows an average deviation of 0.8 kW compared to the measurements. Analysis of recorded real-world bus routes reveals that on average these effects constitute 3.1% of the total powertrain energy. The effect is even more significant for routes crossing city centers, reaching values up to 5.8%. In these cases, cornering losses can be significant and should not be neglected in an accurate energy consumption prediction.     

某赛车转向系统建模与优化

在某赛车转向系统设计过程中,需要对转向系统进行建模和优化,而转向系的优化过程中只需优化梯形臂长m,梯形底角γ。我们利用matlab优化工具箱中fmincon函数来对梯形臂长m和底角γ进行优化。