BMQ-Index: Shared and Incremental Processing of Border Monitoring Queries over Data Streams

Border Monitoring Query (BMQ) has different query semantic from conventional continuous range query. It monitors the values of data streams and reports them only when data streams cross the borders of its range. In this paper, we first emphasize the importance and usefulness of BMQ through attractive service scenarios. Then, we propose BMQ-Index, which is specialized to BMQ evaluation. It efficiently processes a large number of BMQs in a shared and incremental manner. For shared processing, BMQ-Index adopts a query indexing approach, thereby achieving a high level of scalability. For incremental processing, BMQ-Index employs an incremental access method. Thus, successive BMQ evaluations are significantly accelerated. We present an index structure and a search algorithm to support onedimensional as well as multi-dimensional BMQ. Lastly, we demonstrate the performance benefits of BMQ-Index through analysis and experiments.

1. Introduction

Advances in mobile computing and embedded device technologies open up new computing environments. The environments contain numerous data generators such as sensors, probes and agents, which generate data in the form of continuous data stream. In order to monitor such data streams and take proper actions, if needed, users register a large number of range queries or filters which are evaluated continuously [1] [2] [3] [11] [12] [14].