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Efficient Shortest Path Techniques on a Summarized Graph based on the Relationships

관계기반 요약그래프에서 효율적인 최단경로 탐색기법

  • 김현욱 (경희대학교 컴퓨터공학과) ;
  • 서호진 (경희대학교 컴퓨터공학과) ;
  • 이영구 (경희대학교 컴퓨터공학과)
  • Received : 2017.02.09
  • Accepted : 2017.04.12
  • Published : 2017.07.15

Abstract

As graphs are becoming increasingly large, the costs for storing and managing data are increasing continuously. Shortest path discovery over a large graph requires long running time due to frequent disk I/Os and high complexity of the graph data. Recently, graph summarization techniques have been studied, which reduce the size of graph data and disk I/Os by representing highly dense subgraphs as a single super-node. Decompressing should be minimized for efficient shortest path discovery over the summarized graph. In this paper, we analyze the decompression performance of a summarized graph and propose an approximate technique that discovers the shortest path quickly with a minimum error ratio. We also propose an exact technique that efficiently discovered the shortest path by exploiting an index built on paths containing super-nodes. In our experiments, we showed that the proposed technique based on the summarized graph can reduce the running time by up to 70% compared with the existing techniques performed on the original graph.

그래프 데이터가 대용량화됨에 따라 데이터를 저장 및 유지하기 위한 비용이 지속적으로 증가하고 있다. 이와 같은 대용량 그래프에서 최단경로를 탐색하는 것은 빈번한 디스크 I/O와 그래프의 높은 복잡도로 인해 매우 오랜 수행시간을 요구한다. 최근 그래프의 밀집도가 높은 부분그래프를 하나의 슈퍼노드로 표현하여 그래프 크기와 디스크 I/O를 줄이는 그래프 요약 연구가 수행되고 있다. 이와 같은 요약된 그래프에서 효율적으로 최단경로를 탐색하기 위해서는 요약그래프의 복원을 최소화해야 한다. 본 논문에서는 요약그래프의 복원 성능을 분석하고, 이를 이용하여 오차를 최소화하며 빠르게 최단경로를 탐색하는 근사 기법을 제안한다. 또한 최단경로 탐색과정 중 복원이 요구되는 슈퍼노드가 포함된 경로를 사전에 색인으로 구축하여 정확한 최단경로를 효율적으로 탐색하는 기법을 제안한다. 실세계 데이터를 이용한 실험을 통하여 제안하는 요약그래프에서의 최단거리 탐색기법이 원본 그래프를 고려한 기법들보다 최대 70%로 수행시간이 향상되었음을 보인다.

Keywords

Acknowledgement

Supported by : 한국연구재단

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