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Estimating a model of dynamic activity generation based on one-day observations: Method and results 总被引:1,自引:0,他引:1
Theo A. Arentze Dick Ettema Harry J.P. Timmermans 《Transportation Research Part B: Methodological》2011,45(2):447-460
In this paper we develop and explore an approach to estimate dynamic models of activity generation on one-day travel-diary data. Dynamic models predict multi-day activity patterns of individuals taking into account dynamic needs as well as day-varying preferences and time-budgets. We formulate an ordered-logit model of dynamic activity-agenda-formation decisions and show how one-day observation probabilities can be derived from the model as a function of the model’s parameters and, with that, how parameters can be estimated using standard loglikelihood estimation. A scale parameter cannot be identified because information on within-person variability is lacking in one-day data. An application of the method to data from a national travel survey illustrates the method. A test on simulated data indicates that, given a pre-set scale, the parameters can be identified and that estimates are robust for a source of heterogeneity not captured in the model. This result indicates that dynamic activity-based models of the kind considered here can be estimated from data that are less costly to collect and that support the large sample sizes typically required for travel-demand modeling. We conclude therefore that the proposed approach opens up a way to develop large-scale dynamic activity-based models of travel demand. 相似文献
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This article proposes a maximum-likelihood method to update travel behavior model parameters and estimate vehicle trip chain based on plate scanning. The information from plate scanning consists of the vehicle passing time and sequence of scanned vehicles along a series of plate scanning locations (sensor locations installed on road network). The article adopts the hierarchical travel behavior decision model, in which the upper tier is an activity pattern generation model, and the lower tier is a destination and route choice model. The activity pattern is an individual profile of daily performed activities. To obtain reliable estimation results, the sensor location schemes for predicting trip chaining are proposed. The maximum-likelihood estimation problem based on plate scanning is formulated to update model parameters. This problem is solved by the expectation-maximization (EM) algorithm. The model and algorithm are then tested with simulated plate scanning data in a modified Sioux Falls network. The results illustrate the efficiency of the model and its potential for an application to large and complex network cases. 相似文献
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JinYoung Kim Fumitaka Kurauchi Nobuhiro Uno Takeshi Hagihara Takehiko Daito 《智能交通系统杂志
》2014,18(2):190-203
》2014,18(2):190-203
In this study, we explored the potential of using electronic toll collection (ETC)-derived data that are a part of intelligent transport systems (ITS). Dynamic origin–destination (OD) traffic volumes were estimated using ETC data on the Hanshin Expressway. A dynamic OD estimation model that was suggested in a previous study was used, and abundant ETC data were input to improve the estimation accuracy. The results of OD estimation were analyzed to understand traffic demand and its variation. External factors were clarified that have an influence on variances in the OD flows, and statistical analysis methods for the variations were proposed depending on the factors. Moreover, the improvements in traffic simulation accuracy and performance as a result of using ETC data as input variables in the simulation models were discussed. According to the results of this study, ETC data have potential to assist in understaningd traffic demand and its variation, and the results can be applied to network management. 相似文献
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Waterseepageofakarsttunnelsectioninsoilsurroundingrockispronetosurfacesubsidence.Considering the settlement caused by descending of water level due to water leakage, a method of surface settlement estimation under steady seepage of phreatic water was proposed. Based on the seepage and consolidation theory, the changes of dead-weight and seepage effective stress of soil unit in surrounding rock was analyzed in condition of water seepage, and the settlement zone of surrounding rock was divided by taking the funnel curve of precipitation as the boundary line. A two-dimension plane was established based on the excavation cross section and the estimation formula for surface settlement due to seepage effect was deduced by means of double integral. On the basis of Yaozhai tunnel of Liuzhai-Hechi Expressway in Guangxi Zhuang Autonomous Region, the surface settlement of soil surrounding sec⁃ tion was predicted by field measurement and formula estimation respectively. Facts and figures show that the mea⁃ sured values are mainly consistent with the estimation ones, while the measured values are larger than the estima⁃ tion ones within the scope 3 m away from the excavation face along the horizontal radial direction. © 2018, Editorial Office of "Modern Tunnelling Technology". All right reserved. 相似文献
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LMS自适应时延估计法在被动定位系统中的应用研究 总被引:3,自引:0,他引:3
小均方(LMS)自适应时延估计法不依赖于输入信号和噪声的统计先验知识而可以跟踪动态或时变的环境和参数,算法亦比较简单。计算机仿真和湖试分析数据分析表明,将LMS自适应时延估计法应征地被动定位系统,可以获得较高的定位精度,另外,对影响被动定位精度的因素进行了分析。 相似文献
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国际工程报价中汇率风险费的估算 总被引:1,自引:1,他引:0
弭尚宝 《铁路工程造价管理》2010,25(4):8-11
在人民币升值的巨大压力下,在确定国际工程投标报价时,汇率风险在风险分析中的地位越发重要,如果在投标阶段不能合理估算汇率风险费用就有可能使项目蒙受经济损失,从而严重影响涉外施工企业的经济效益。此文重点讨论在国际工程投标报价编制阶段,如何对报价组成中的涉汇费用进行分析,并以此为基础估算汇率风险费用。汇率风险费的估算可以有效规避汇率波动对项目造成的经营风险,保持企业经济效益的稳定。 相似文献
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《Vehicle System Dynamics: International Journal of Vehicle Mechanics and Mobility》2012,50(6):549-563
Sideslip angle could provide important information concerning vehicle's stability. Unfortunately direct measurement of sideslip angle requires a complex and expensive experimental set-up, which is not suitable for implementation on ordinary passenger cars; thus, this quantity has to be estimated starting from the measurements of vehicle lateral/longitudinal acceleration, speed, yaw rate and steer angle. According to the proposed methodology, sideslip angle is estimated as a weighted mean of the results provided by a kinematic formulation and those obtained through a state observer based on vehicle single-track model. Kinematical formula is considered reliable for a transient manoeuvre, while the state observer is used in nearly quasi-state condition. The basic idea of the work is to make use of the information provided by the kinematic formulation during a transient manoeuvre to update the single-track model parameters (tires cornering stiffnesses). A fuzzy-logic procedure was implemented to identify steady state or transient conditions. 相似文献