2,557 research outputs found

    A Novel Trip Planner Using Effective Indexing Structure

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    ABSTRACT: The administration of transportation frameworks has ended up progressively imperative in numerous genuine applications such as area based administrations, production network administration, movement control, et cetera. These applications normally include questions over spatial street systems with powerfully changing and confused activity conditions. In this paper, we model such a system by a probabilistic time-dependent graph (PTGraph), whose edges are connected with unverifiable postponement capacities. We propose a valuable inquiry in the PT-Graph, in particular an Trip planner query (TPQ), which recovers excursion arranges that cross a set of inquiry focuses in PT-Graph, having the base voyaging time with high certainty. To handle the proficiency issue, we display the pruning systems time interim pruning and probabilistic pruning to viably discount bogus alerts of trek arrangements. Besides, we outline a pre computation method in view of the expense model and develop a list structure over the pre computed information to empower the pruning by means of the file. We coordinate our proposed pruning techniques into a productive question system to answer TPQs. Through far reaching tests, we exhibit the proficiency and adequacy of our TPQ question noting methodology

    Optimal Time-dependent Sequenced Route Queries in Road Networks

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    In this paper we present an algorithm for optimal processing of time-dependent sequenced route queries in road networks, i.e., given a road network where the travel time over an edge is time-dependent and a given ordered list of categories of interest, we find the fastest route between an origin and destination that passes through a sequence of points of interest belonging to each of the specified categories of interest. For instance, considering a city road network at a given departure time, one can find the fastest route between one's work and his/her home, passing through a bank, a supermarket and a restaurant, in this order. The main contribution of our work is the consideration of the time dependency of the network, a realistic characteristic of urban road networks, which has not been considered previously when addressing the optimal sequenced route query. Our approach uses the A* search paradigm that is equipped with an admissible heuristic function, thus guaranteed to yield the optimal solution, along with a pruning scheme for further reducing the search space. In order to compare our proposal we extended a previously proposed solution aimed at non-time dependent sequenced route queries, enabling it to deal with the time-dependency. Our experiments using real and synthetic data sets have shown our proposed solution to be up to two orders of magnitude faster than the temporally extended previous solution.Comment: 10 pages, 12 figures To be published as a short paper in the 23rd ACM SIGSPATIA

    A game-theoretic approach for reliability evaluation of public transportation transfers with stochastic features

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    A game-theoretic approach based on the framework of transferable-utility cooperative games is developed to assess the reliability of transfer nodes in public transportation networks in the case of stochastic transfer times. A cooperative game is defined, whose model takes into account the public transportation system, the travel times, the transfers and the associated stochastic transfer times, and the users’ demand. The transfer stops are modeled as the players of such a game, and the Shapley value – a solution concept in cooperative game theory – is used to identify their centrality and relative importance. Theoretical properties of the model are analyzed. A two-level Monte Carlo approximation of the vector of Shapley values associated with the nodes is introduced, which is efficient and able to take into account the stochastic features of the transportation network. The performance of the algorithm is investigated, together with that of its distributed computing variation. The usefulness of the proposed approach for planners and policy makers is shown with a simple example and on a case study from the public transportation network of Auckland, New Zealand

    A dynamic ridesharing dispatch and idle vehicle repositioning strategy with integrated transit transfers

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    We propose a ridesharing strategy with integrated transit in which a private on-demand mobility service operator may drop off a passenger directly door-to-door, commit to dropping them at a transit station or picking up from a transit station, or to both pickup and drop off at two different stations with different vehicles. We study the effectiveness of online solution algorithms for this proposed strategy. Queueing-theoretic vehicle dispatch and idle vehicle relocation algorithms are customized for the problem. Several experiments are conducted first with a synthetic instance to design and test the effectiveness of this integrated solution method, the influence of different model parameters, and measure the benefit of such cooperation. Results suggest that rideshare vehicle travel time can drop by 40-60% consistently while passenger journey times can be reduced by 50-60% when demand is high. A case study of Long Island commuters to New York City (NYC) suggests having the proposed operating strategy can substantially cut user journey times and operating costs by up to 54% and 60% each for a range of 10-30 taxis initiated per zone. This result shows that there are settings where such service is highly warranted

    Efficient query processing over uncertain road networks

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    One of the fundamental problems on spatial road networks has been the shortest traveling time query, with applications such as location-based services (LBS) and trip planning. Algorithms have been made for the shortest time queries in deterministic road networks, in which vertices and edges are known with certainty. Emerging technologies are available and make it easier to acquire information about the traffic. In this paper, we consider uncertain road networks, in which speeds of vehicles are imprecise and probabilistic. We will focus on one important query type, continuous probabilistic shortest traveling time query (CPSTTQ), which retrieves sets of objects that have the smallest traveling time to a moving query point q from point s to point e on road networks with high confidences. We propose effective pruning methods to prune the search space of our CPSTTQ query, and design an efficient query procedure to answer CPSTTQ via an index structure

    Estimation of bus connection risk with the use of open bus data

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    Bus connection risk estimation has not been studied well despite its potential impact on travellers decisions about the choice of transportation mode and loyalty to public transportation. We aim to develop a framework to estimate and visualize bus connection chance with the use of open bus data. This thesis presents two original models for estimation of bus connection risk based on probability distributions. The first model refers to Bayesian analysis and beta distribution functions. This model depends on the possibility of calculating parameters for all possible bus connections, which is problematic since such data are not stored but rather generated during actual planning of the itinerary. The second model allows us to calculate distribution parameters for arrivals of each feeder bus at the alighting stop and departures of each connecting bus from the boarding stop. It is possible to aggregate historical open bus data to the list of distribution parameters on a regular basis, which only requires setting automatic jobs of preparing and processing data, calculating distribution parameters, and loading them to a planning graph of a trip planner. The framework consists of the theoretical description and practical application, which makes it useful for transportation systems decision-makers, developers, researchers, and end users. The framework has been applied successfully in the city of Tampere, Finland. As a result, the web trip planner with estimation of bus connection chance is ready to use by the public
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