25 research outputs found

    On the capacity and normalisation of ISI channels

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    [Abstract]: We investigate the capacity of various ISI channels with additive white Gaussian noise. Previous papers showed a minimum Eb/N0 of −4.6 dB, 3 dB below the capacity of a flat channel, is obtained using the water-pouring capacity formulas for the 1 + D channel. However, these papers did not take into account that the channel power gain can be greater than unity when water-pouring is used. We present a generic power normalization method of the channel frequency response, namely peak bandwidth normalisation, to facilitate the fair capacity comparison of various ISI channels. Three types of ISI channel, i.e., adder channels, RC channels and magnetic recording channels, are examined. By using our channel power gain normalization, the capacity curves of these ISI channels are shown

    Real time traffic models, decision support for traffic management

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    Reliable and accurate short-term traffic state prediction can improve the performance of real-time traffic management systems significantly. Using this short-time prediction based on current measurements delivered by advanced surveillance systems will support decision-making processes on various control strategies and enhance the performance of the overall network. By taking proactive action deploying traffic management measures, congestion may be prevented or its effects limited. An approach of short-term traffic state prediction is presented and implemented in a real life case for the city of Assen in the Netherlands. This prediction is based on connecting online traffic measurements with a real time traffic model using the macroscopic dynamic traffic assignment model StreamLine in a rolling horizon implementation. Different monitoring data sources consisting of both fixed-point and floating car data are used. The advantage of the rolling horizon approach is that no warming-up period is needed for the dynamic traffic assignment taking less computation time while keeping results consistent. Further, the current traffic state estimation is done by combining model estimates of previous predictions and current measurements. The results of predictions made in the real life case are presented as well as several tested methods for improving the current state estimations showing promising results

    Proyecto piloto 9x18, una alternativa a la expansión de Santiago

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    Ponencia que describe el proyecto píloto 9x18 que consiste en la construcción de una nueva vivienda para los allegados en los lotes donde habitan, sin necesidad de adquirir un terreno nuevo

    Nieuwe verbindingen in verkeersmodellen

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    Transport and PlanningCivil Engineering and Geoscience

    A dynamic traffic assignment model: Theory and applications

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    Civil Engineering and Geoscience

    Using BIG data in transport modelling

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    Both innovation and ingenuity are required to turn an increasing amount of data that is not obviously 'transport oriented' into useful information that can assist with model building in circumstances where relevant data is otherwise not available or in poor supply, explains Omnitrans'Transport and PlanningCivil Engineering and Geoscience

    Requirements for traffic assignment models for strategic transport planning: A critical assessment

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    Transport & PlanningCivil Engineering and Geoscience

    Using metro smart card data to model location choice of after-work activities: an application to Shanghai

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    A location choice model explains how travellers choose their trip destinations especially for those activities which are flexible in space and time. The model is usually estimated using travel survey data; however, little is known about how to use smart card data (SCD) for this purpose in a public transport network. Our study extracted trip information from SCD to model location choice of after-work activities. We newly defined the metrics of travel impedance in this case. Moreover, since socio-demographic information is missing in such anonymous data, we used observable proxy indicators, including commuting distance and the characteristics of one's home and workplace stations, to capture some interpersonal heterogeneity. Such heterogeneity is expected to distinguish the population and better explain the difference of their location choice behaviour. The approach was applied to metro travellers in the city of Shanghai, China. As a result, the model performs well in explaining the choices. Our new metrics of travel impedance to access an after-work activity result in a better model fit than the existing metrics and add additional interpretability to the results. Moreover, the proxy variables distinguishing the population seem to influence the choice behaviour and thus improve the model performance
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