Distributed Processing of k Shortest Path Queries over Dynamic Road Networks
Ziqiang Yu, Xiaohui Yu, Nick Koudas, Yang Liu, Yifan Li, Yueting Chen, Dingyu Yang
备注：
A shorter version of this technical report has been accepted for publication as a full paper in ACM SIGMOD 2020: International Conference on Management of Data
The problem of identifying the k-shortest paths (KSPs for short) in a dynamic road network is essential to many location-based services. Road networks are dynamic in the sense that the weights of the edges in the corresponding graph constantly change over time, representing evolving traffic conditions. Very often such services have to process numerous KSP queries over large road networks at the same time, thus there is a pressing need to identify distributed solutions for this problem. However, most existing approaches are designed to identify KSPs on a static graph in a sequential manner (i.e., the (i+1)-th shortest path is generated based on the i-th shortest path), restricting their scalability and applicability in a distributed setting. We therefore propose KSP-DG, a distributed algorithm for identifying k-shortest paths in a dynamic graph. It is based on partitioning the entire graph into smaller subgraphs, and reduces the problem of determining KSPs into the computation of partial KSPs in relevant subgraphs, which can execute in parallel on a cluster of servers. A distributed two-level index called DTLP is developed to facilitate the efficient identification of relevant subgraphs. A salient feature of DTLP is that it indexes a set of virtual paths that are insensitive to varying traffic conditions, leading to very low maintenance cost in dynamic road networks. This is the first treatment of the problem of processing KSP queries over dynamic road networks. Extensive experiments conducted on real road networks confirm the superiority of our proposal over baseline methods.
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COL-Trees: Efficient Hierarchical Object Search in Road Networks
Center for Computational Science, RIKEN（计算科学中心，RIKEN）；Faculty of Information Technology, Monash University（信息科技学院，墨尔本大学）；Department of Computer and Information Science, University of Konstanz（计算机与信息科学系，康斯坦茨大学）
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