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On October 25, 1995, seven fatalities occurred during a train collision with a school bus crossing railroad tracks adjacent to a signalized intersection in Fox River Grove, IL. In 1996 the National Transportation Safety Board (NTSB): Highway/Railroad Accident Report # PB96-916202 made several recommendations to the the United States Secretary of Transportation, one of which was “… the use and maintenance of railroad and highway traffic signal recording devices…….to readily determine that the highway signals and railroad-activated warning devices are coordinated and operating properly.” To date, this particular recommendation had not been addressed.^ This dissertation proposes (1) screening and prioritizing procedure for signalized intersection adjacent to highway-railroad crossings, (2) performance measures to evaluate track clearing...
This lead paper examines the status of high-speed rail in the United States within the context of emerging megaregions. It reflects on the current state of high-speed rail planning globally and examines its link to economic planning and enhanced mobility systems.
A keynote presentation for the International Transport Forum May 3, 2012 in Leipzig, Germany. Run-time: 13:42 minutes
We consider MC-CDMA schemes, with reduced envelope fluctuations. Both CP-assisted (cyclic prefix) and ZP (zero-padded) MC-CDMA schemes are addressed. We develop turbo FDE (frequency-domain equalization) schemes, combined with cancelation of nonlinear distortion effects. The proposed turbo receivers allow significant performance improvements at low and moderate SNR, even when the transmitted signals have reduced envelope fluctuations.
The MC-CDMA techniques (multicarrier code division multiple access) combine a CDMA scheme with OFDM modulation (orthogonal frequency division multiplexing), so as to allow high transmission rates over severely time-dispersive channels without the need of a complex receiver implementation. We propose an iterative frequency-domain decision-feedback receiver for MC-CDMA signals. The proposed receiver has excellent performance, close to the single-code MFB (matched filter bound), even for severe time-dispersive scenarios and/or in the presence of strong interfering channels.
Whenever a DS-CDMA signal (direct sequence code division multiple access) is the sum of several components associated to different spreading codes (e.g., the DS-CDMA signal to be transmitted by the BS (Base Station) in the downlink, or any multicode DS- CDMA signal), it has high envelope fluctuations, and a high PMEPR (Peak-to-Mean Envelope Power Ratio) setting strong linearity requirements for the power amplifiers. For this reason, it is desirable to reduce the envelope fluctuations of the transmitted signals. A promising class of nonlinear signal processing schemes, combining a nonlinear operation in the time- domain with a linear, frequency-domain filtering operation, was recently proposed for reducing the envelope fluctuations (and, inherently, the PMEPR) of DS-CDMA signals, while maintaining the spectral occupation of the correspo...
The study analyzes trends and policies regarding developments of public and private transport in large cities of developing countries. The importance of public transport for these cities is extremely great because of their large low-income populations. It is found that improved public transport is the basic component of any solution for improvement of mobility and reduction of congestion and chaotic traffic conditions in these cities. Most cities cannot afford to build a road network required to accommodate unrestrained travel by private automobiles.^ Considerable economies and improved services can be achieved by better organization of present buses and jitneys, but the modes cannot by themselves provide either required high capacities or improved levels of service in major, heavily travelled corridors in large cities of developing...
The urban transportation model predicts flows on a transportation network as a function of the urban system containing the network and the characteristics of the transportation network. It comprises four steps: (1) trip generation, (2) trip distribution, (3) modal split, and (4) traffic assignment. The fourth step, traffic assignment, predicts routes (paths) used between each origin-destination pair on the transportation network.^ Calibration of traffic assignment models is acknowledged as a perquisite to their application. Such calibration efforts have traditionally been ad hoc. They have fallen into one of five categories: (1) modification of the network representation, (2) adjustment of travel demand, (3) selecting the traffic assignment method and assumptions, (4) adjustment of the traffic dispersion parameter for stochastic ass...
The study objective is to develop a mutimodal urban transportation pricing theory based on a proposed benefit measurement model of transportation system or policy changes and to provide a traffic demand projection model.^ The benefit measurement model is developed in the context of multimodes (namely, a highway mode and an urban rail transit mode) and general equilibrium with income by incorporating Marshallian demand, a time element, and the distinction between consumption and production goods. The model development starts with general utility maximization consumer behavior, and ends with a simulation of economic and financial benefits in terms of transportation variables.^ By assuming, first, that both the automobile toll and transit fare are policy administered, such evaluation criteria as consumer surpluses, suppliers' revenu...
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