13,758 research outputs found

    An Integrated Bus and Taxi Routes for a Mobile Trip Planning System

    Get PDF
    With the popular usage of Google Maps and smart phones, more and more people are using smart phones to surf and inquire about travel information. As a result, every major city plans to push the existing online public transportation trip planning system beyond traditional computer users to mobile phone users. The trip planning system is based on the starting and ending points that a user inputs, and guides the user to take a bus or metro through an electronic map interface. The system usually provides different kind of alternative travel routes with the estimated time of arrival. However, people who use the public transport system may encounter some uncertainties, such as long waiting times, long routes, long walking distances, etc. In each big city, the taxi is a universal transport vehicle which is available at almost anytime, anywhere. Taxis can save passengers’ walking distance and travel time with a deficit of high cost. Therefore, we design a trip planning system to unify the Taipei public transportation system with taxis. The users can inquire of a travel route through the mobile phones. This system uses Google Maps as a base map. The users assign an upper limit of fare which they are willing to pay. The system will balance between travel time and travel cost to obtain a route which may combine usage of the bus and taxi. Because of the high density of bus stations in Taipei city, the route search may consume a lot of system resources. We propose an improvement method to eliminate some intermediate bus stations in route search processing

    The FEM-Prediction on tensile performance of woven membrane materials under uni and Bi-axial loads

    Get PDF
    In this study, the mechanical model of the woven PVC-coated membrane materials has been built. By the FEM analysis, it was found out that when tensioned under uni-axial loads, the tensile modulus in the warp and fill direction of woven membrane materials could be predicted nicely, especially after the revision of the properties for the fiber materials. The effect of the tensile moduli of the fiber and the PVC coating materials on the modulus of the woven membrane fabrics has been discussed. It could be consulted that with the proper improvement of the modulus of the fiber materials in the fill direction, the discrepancy between the modulus of woven membrane materials in the warp and fill direction could be reduced to a certain extent. When it comes to the prediction of the modulus of the woven membrane materials under bi-axial loads, large difference could be noticed between the predicted results and the experimental results, especially in warp direction. This was due to the fact that the mechanical analysis model could only show the differences of the geometry configuration between the warp and fill directions. However, the reinforcement of membrane materials in warp direction during weaving and coating processes has been ignored

    Field-emission characteristics of conical boron nitride nanorods

    Get PDF
    We present the electron field-emission (FE) characteristics of conical boron nitride nanorods grown on a (1 0 0) n-type silicon substrate. The emission current can be up to ∼60 νA at an applied voltage of ∼3 kV. Two distinct slopes are evident in th

    Universal Global Imprints of Genome Growth and Evolution – Equivalent Length and Cumulative Mutation Density

    Get PDF
    BACKGROUND: Segmental duplication is widely held to be an important mode of genome growth and evolution. Yet how this would affect the global structure of genomes has been little discussed. METHODS/PRINCIPAL FINDINGS: Here, we show that equivalent length, or L(e), a quantity determined by the variance of fluctuating part of the distribution of the k-mer frequencies in a genome, characterizes the latter's global structure. We computed the L(e)s of 865 complete chromosomes and found that they have nearly universal but (k-dependent) values. The differences among the L(e) of a chromosome and those of its coding and non-coding parts were found to be slight. CONCLUSIONS: We verified that these non-trivial results are natural consequences of a genome growth model characterized by random segmental duplication and random point mutation, but not of any model whose dominant growth mechanism is not segmental duplication. Our study also indicates that genomes have a nearly universal cumulative "point" mutation density of about 0.73 mutations per site that is compatible with the relatively low mutation rates of (1-5) x 10(-3)/site/Mya previously determined by sequence comparison for the human and E. coli genomes
    • …
    corecore