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101.
A new approach in recognizing travel mode choice patterns is proposed, based on the Support Vector Machine classification technique. The tour-based travel demand dataset that is analysed is for New York State, derived from the 2009 U.S. National Household Travel Survey. The main features characterizing each tour are the means used, travel-related variables and socioeconomic aspects. Results obtained demonstrate the ability to predict to some extent, in real settings where car use dominates, which tours are likely to be made by public transport or non-motorized means. Moreover, the flexibility of the technique allows assessing the predictive power of each feature according to the combination of travel means used in different tours. Potential applications range from activity-based travel choice simulators to search engines supporting personalized travel planners – in general, whenever ‘best guesses’ on mode choice patterns have to be made quickly on large amounts of data prejudicing the possibility of setting up a statistical model. 相似文献
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103.
Raj Bridgelall 《运输规划与技术》2013,36(8):711-737
Parking demand is a significant land-use problem in campus planning. The parking policies of universities and large corporations with facilities located in small urban areas shape the character of their campuses. These facilities will benefit from a simplified methodology to study the effects of parking availability on transportation mode mix and impacts on recruitment and staffing policies. This paper, based on a case study of North Dakota State University in the United States, introduces an analytical framework to provide planners with insights about how parking supply and demand affects campus transportation mode choice. The methodology relies only on aggregate mode choice data for the special generator zone and the average aggregate volume/capacity ratio projections for all external routes that access the zone. This reduced data requirement significantly lowers analysis cost and obviates the need for specialized modelling software and spatial network analysis tools. Results illustrate that the framework is effective for analysing mode choice changes under different scenarios of parking supply and population growth. 相似文献
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105.
This study considers advanced statistical approaches for sequential data assimilation. These are explored in the context of nowcasting and forecasting using nonlinear differential equation based marine ecosystem models assimilating sparse and noisy non-Gaussian multivariate observations. The statistical framework uses a state space model with the goal of estimating the time evolving probability distribution of the ecosystem state. Assimilation of observations relies on stochastic dynamic prediction and Bayesian principles. In this study, a new sequential data assimilation approach is introduced based on Markov Chain Monte Carlo (MCMC). The ecosystem state is represented by an ensemble, or sample, from which distributional properties, or summary statistical measures, can be derived. The Metropolis-Hastings based MCMC approach is compared and contrasted with two other sequential data assimilation approaches: sequential importance resampling, and the (approximate) ensemble Kalman filter (including computational comparisons). A simple illustrative application is provided based on a 0-D nonlinear plankton ecosystem model with multivariate non-Gaussian observations of the ecosystem state from a coastal ocean observatory. The MCMC approach is shown to be straightforward to implement and to effectively characterize the non-Gaussian ecosystem state in both nowcast and forecast experiments. Results are reported which illustrate how non-Gaussian information originates, and how it can be used to characterize ecosystem properties. 相似文献
106.
区域间港口国监督的发展现状及实施比较 总被引:1,自引:0,他引:1
于晓丹 《武汉船舶职业技术学院学报》2006,5(4):12-15,33
为消除低标准船、加强海上安全、保护海洋环境及改善船员生活与工作条件,区域性港口国监督制度已经成为一项成效显著的利器并得到全球共识。从1982年3月巴黎备忘录成立以来,经过二十多年的发展,全球已建立九个区域性的港口国监督。本文重在介绍九大港口国监督区域的发展现状,并比较其实施的效果,拟供完善我国港口国监督制度的参考。 相似文献
107.
基于状态空间法的受电弓主动控制的研究 总被引:4,自引:0,他引:4
建立线性化的受电弓模型和接触网的有限元模型、以及它们的耦合系统动力学模型,分析接触网的刚度变化,利用最优控制理论对主动控制式受电弓进行了理论上的研究。根据高速铁路对受电弓和接触网动力学性能的要求,从降低接触压力的波动以改善受流质量着手,针对弓网关系的特点,建立了受电弓主动控制系统模型,采用全状态反馈设计并利用线性二次型最优控制策略设计了受电弓主动控制的控制器,并求得了控制器参数。对控制系统进行仿真验证和研究。结果表明,采用主动控制式受电弓,能够降低接触压力的波动,提高弓网系统的动态性能,改善受流质量。 相似文献
108.
王健 《筑路机械与施工机械化》2000,17(4):18-19
通过对振动压路机振动轴承烧损原因的分析,提出为避免轴承烧损,在装配、使用和维护中应注意的问题和解决办法。 相似文献
109.
电池管理系统(BMS)采用了防止电池过放电和过充,提供电池均衡控制,能够实现新能源汽车动力锂电池的最佳利用和保护。电池管理系统实时精准估算电池电荷状态(SOC)是提高电动汽车续航里程和延长寿命的关键。然而,SOC不能直接测量,动力电池的充、放电又是一个复杂过程,导致目前现有的SOC估算策略很难精确地估算出实时在线SOC值。因此,如何提高SOC估算精度是当下BMS领域的研究热点。本文通过对各种SOC估算方法进行文献综述,分析和总结各个SOC估算方法的原理及优缺点,提出SOC估计策略未来发展趋势。 相似文献
110.
简要介绍大跨桥梁健康监测系统的发展,并结合润扬长江大桥健康监测系统,介绍了桥梁健康监测系统的组成、监测内容、功能及特点。对几种桥梁结构常用的健康状态评估方法进行了分析比较,最后探讨了健康监测领域今后的主要研究问题和发展方向。 相似文献