Although recent budgetary considerations by the Federal govenment do not portend well for urban public transit, some transit systems are considering expansion into less densely-settled areas further from the Central Business District. Of some concern to planners has been their belief that suburban and rural dwellers may be much less inclined than urban dwellers to support expansion of transit service. This paper presents an analysis of a random-digit dialing/mail-out, mail-back survey conducted in Washtenaw County, Michigan which was designed specifically to examine differences in attitudes between urban and rural residents. Six mutually-exclusive spatial strata were established based upon population density. This paper tests for expected spatial differences in socioeconomic and demographic variables and then examines spatial variations in attitudes toward public transportation. The major conclusion is that the expected spatial variations in attitudes about transit service provision between the spatial strata do not arise. Most of the significant differences found are with respect to questions which relate to where transit is provided. Residents in rural (urban) areas support more strongly the provision of services to rural (urban) areas. Many residents, however, will support transit service that may not benefit them directly. 相似文献
Transportation - Ride-hailing (ridesourcing) companies such as Uber, Lyft, and Didi Chuxing have been a disruptive force in the urban mobility landscape around the world during the past decade. In... 相似文献
Freight forecasting models have been significantly improved in recent years, especially in the field of goods vehicle behavior modeling. On the other hand, the improvements to commodity flow modeling, which provide inputs for goods vehicle simulations, were limited. Contributing to this component in urban freight modeling systems, we propose an error component logit mixture model for matching a receiver to a supplier that considers two-layers in supplier selection: distribution channels and specific suppliers. The distribution channel is an important element in freight modeling, as the type of distribution channel is relevant to various aspects of shipments and vehicle trips. The model is estimated using the data from the Tokyo Metropolitan Freight Survey. We demonstrate how typical establishment survey data (i.e. establishment and outbound shipment records) can be used to develop the model. The model captures the correlation structure of potential suppliers defined by business function and provides insights on the differences in the supplier choice by distribution channel. The reproducibility tests confirm the validity of the proposed approach, which is currently integrated into a metropolitan-scale agent-based freight modeling system, for practical use.
The economic value of the oceans and maritime industry is strongly gaining in importance. As the oceans are very large and particularly sensitive ecosystems, which need to be preserved, a balance between the use and the protection of the seas has to be found. On this issue, the paper presents some thoughts starting with a brief analysis of what to understand by maritime industry which is labeled as blue economy, and a recapitulation of the main threats for the marine environment, caused by blue economy. After that, some noteworthy prerequisites and criteria for finding a sound balance between the use and the protection of the seas will be highlighted, especially the need for sustainable ocean governance is put to discussion. 相似文献
Optimal sequence for clearing snow from the manoeuvring area of an airport.
Contains optimising algorithms solved using CPLEX LP‐based tree search.
Restrictions on partial fulfilment of operational targets applied to subsets of significant stretches, used for planning the operation of snow‐clearing machines.
Model applied to the case of the manoeuvring area of Adolfo Suárez Madrid Barajas Airport.
Conclusions are given on the results of the computational tests carried out. There are five models of the manoeuvring area which cover increasingly complex situations and larger areas.
Oscillating point absorber buoys may rise out of the water and be subjected to bottom slamming upon re-entering the water.
Numerical simulations are performed to estimate the power absorption, the impact velocities and the corresponding slamming
forces for various slamming constraints. Three buoy shapes are considered: a hemisphere and two conical shapes with deadrise
angles of 30° and 45°, with a waterline diameter of 5 m. The simulations indicate that the risk of rising out of the water
is largely dependent on the buoy draft and sea state. Although associated with power losses, emergence occurrence probabilities
can be significantly reduced by adapting the control parameters. The magnitude of the slamming load is severely influenced
by the buoy shape. The ratio between the peak impact load on the hemisphere and that on the 45° cone is approximately 2, whereas
the power absorption is only 4–8% higher for the 45° cone. This work illustrates the need to include slamming considerations
aside from power absorption criteria in the buoy shape design process and the control strategy. 相似文献