微观仿真在城市停车设施规划中的应用

为研究停车场规划和可达性对城市路网的影响,在世界范围内的三个不同城市应用微观仿真模型模拟停车设施规划。描述了三个城市采用的不同研究方法及得到的研究结果。三项研究都试图找到由驾驶人寻找停车位而造成的城市交通拥堵的解决方法。同时,在测试设计方案时,都使用了S-Paramics微观仿真模型。     

新的美国公路桥抗震设计指导规范

本文简要地讨论了美国国家公路与运输协会新的桥梁抗震指导规范的主要变化.该修订规范是由国家公路合作研究规划项目于2006年5月完成的.拟被美国国家公路与运输协会采用,国家公路合作研究规划项目20-07/专题193于2007年被正式采用.     

The value of travel time savings in freight transport: a meta-analysis

Transportation - The value of freight travel time savings (VFTTS) is a monetary value that is considered an important input into cost–benefit analysis and traffic forecasting. The VFTTS is...     

Do transportation network companies increase or decrease transit ridership? Empirical evidence from San Francisco

Transportation - Transportation network companies (TNCs), such as Uber and Lyft, have been hypothesized to both complement and compete with public transit. Existing research on the topic is limited...     

New appraisal values of travel time saving and reliability in Great Britain

Transportation - This paper provides an overview of the study ‘Provision of market research for value of time savings and reliability’ undertaken by the Arup/ITS Leeds/Accent consortium...     

Creating synthetic baseline populations

To develop activity-based travel models using microsimulation, individual travelers and households must be considered. Methods for creating baseline synthetic populations of households and persons using 1990 census data are given. Summary tables from the Census Bureau STF-3A are used in conjunction with the Public Use Microdata Sample (PUMS), and Iterative Proportional Fitting (IPF) is applied to estimate the proportion of households in a block group or census tract with a desired combination of demographics. Households are generated by selection of households from the associated PUMS according to these proportions. The tables of demographic proportions which are exploited here to make household selections from the PUMS may be used in traditional modeling. The procedures are validated by creating pseudo census tracts from PUMS samples and considering the joint distribution of the size of households and the number of vehicles in the households. It is shown that the joint distributions created by these methods do not differ substantially from the true values. Additionally the effects of small changes in the procedure, such as imputation of additional demographics and adding partial counts to the constructed demographic tables are discussed in the paper.     

TARGETED ACTIVATION OF CD_（8）~（＋） CELLS AND INFECTION OF β_2－MICROGLOBULIN－DEFICIENT MICE FAIL TO CONFIRM A PRIMARY PROTECTIVE

ＴＡＲＧＥＴＥＤＡＣＴＩＶＡＴＩＯＮＯＦＣＤ_（８）~（＋）ＣＥＬＬＳＡＮＤＩＮＦＥＣＴＩＯＮＯＦβ_２－ＭＩＣＲＯＧＬＯＢＵＬＩＮ－ＤＥＦＩＣＩＥＮＴＭＩＣＥ　ＦＡＩＬＴＯＣＯＮＦＩＲＭＡＰＲＩＭＡＲＹＰＲＯＴＥＣＴＩＶＥＲＯＬＥＦＯＲＣＤ（８）~（＋...     

EFFECT OF GRINDING TISSUE ON ISOLATE RECOVERY FROM RABBIT CORNEAS WITH FUNGAL KERATITIS

ＥＦＦＥＣＴＯＦＧＲＩＮＤＩＮＧＴＩＳＳＵＥＯＮＩＳＯＬＡＴＥＲＥＣＯＶＥＲＹＦＲＯＭＲＡＢＢＩＴＣＯＲＮＥＡＳＷＩＴＨＦＵＮＧＡＬＫＥＲＡＴＩＴＩＳＲｉｃｈａｒｄＲｏｂｉｎｓｏｎ，ＹａｎｇＲｏｎｇ；Ｗ．ＳｔｅｖｅｎＨｅａｄ，ＤｅｎｔｓＯ＇Ｄａｙ（Ｄ...     

Assessment of wind quality for oceanographic modelling in semi-enclosed basins

The quality of surface winds derived from four meteorological models is assessed in the semi-enclosed Adriatic Sea over a 2-month period: a global hydrostatic model ECMWF T511 (40 km resolution), a hydrostatic limited area model LAMBO (20 km), and two non-hydrostatic limited area models: LAMI (7 km) and COAMPS™ (4 km). These wind models are used to drive a 2 km resolution wave model (SWAN) of the Adriatic, and wind and wave results are compared with observations at the ISMAR oceanographic tower off Venice. Waves are also compared at buoy locations near Ancona and Ortona. Consistently with earlier studies, the ECMWF fields underestimate the wind magnitude and do not reproduce the known spatial structure of strong wind events. The results show that the higher-resolution, limited area models LAMI and COAMPS exhibit better amplitude response than the coarser ECMWF: there is a 3- to 4-fold reduction of the wind underestimation at the platform (from 36% to 8–11%). The wave response is also improved with LAMI and COAMPS: there is a 2-fold reduction in the underestimation of wave heights at the platform. These non-hydrostatic models also produce wind fields with more realistic small-scale, spatial structure during strong wind events. The temporal correlation between observed and modelled wind, however, is highest with the global ECMWF model due to the fact that large-scale features can be predicted deterministically, whereas small-scale features can only be predicted stochastically. Models with less small-scale structure have better correlation because they have less “noise.” This explanation is supported by increased correlation between modelled and observed waves, the waves representing a smoothing of the wind over fetch and duration. Although there is room for improvement, the high-resolution, non-hydrostatic models (LAMI and COAMPS) offer significant advantages for driving oceanographic simulations in semi-enclosed basins such as the Adriatic Sea.