Top-k queries in uncertain databases are quite popular and useful due to its wide application usage. However, compared to Top-k in traditional databases, queries over uncertain database are more complicated because of...
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Existing research on extreme value query in wireless sensor networks is mainly focus on finding out sensors with highest metric. Yet in most actually scenarios, people cares more about special network regions than det...
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The paper studies the management problem of data provenance. Firstly, two data models, which enhance the traditional relational model and tree model, are proposed to reveal the basic nature of data provenance. To answ...
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A Top-k aggregate query ranks groups of tuples by their aggregate values, sum or average for example, and returns k groups with the highest aggregate values. We propose a dynamic programming based method to process un...
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Reliable telecommunication applications in future need the supports from replication real-time main memory databases. In order to improve recovery performance and provide predictable recovery, this paper proposes a ne...
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In mobile computing environment, the features of limited resources, frequent disconnection and long transactions make the success rate of mobile distributed real-time transactions low. Through analyzing the factors im...
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With the significant advantages of RFID technologies, RFID is being gradually adopted and deployed in a wide area of applications, such as supply chain and logistics. Since RFID data has the characteristics including ...
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Ranking is one of the key factors for efficient and effective XML information retrieval. Compared with traditional IR, XML information retrieval has introduced many new challenges, one of which is that the traditional...
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In this paper, a rapid resynchronization method using intent logs is suggested for replication in-memory databases supporting mobile communication applications. Both the identifiers of unsynchronized segments and the ...
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In this paper, a rapid resynchronization method using intent logs is suggested for replication in-memory databases supporting mobile communication applications. Both the identifiers of unsynchronized segments and the identifiers of the slaves who have missed the updates in the segments are recorded in the intent logs. When receiving a resynchronization request from a slave, the master will scan the intent logs to find the unsynchronized segments for the salve, and then send the segments gotten directly from its memory to the slave. The performance results shown the intent logs method can reduce resynchronization time than methods using transaction logs.
Reverse Skyline Queries have been proved very useful in business location, environmental monitoring and some other applications. In this paper, we consider reverse skyline queries processing on data stream, which prov...
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Reverse Skyline Queries have been proved very useful in business location, environmental monitoring and some other applications. In this paper, we consider reverse skyline queries processing on data stream, which provides continuous, high-speed data elements. Specifically, we consider the latest objects in the sliding window. The challenge is that it is difficult to maintain a multidimensional index (for example, R-tree) in a dynamic dataset. Focusing on this challenge, we propose an algorithm with a DC-Tree as index and effective pruning methods to reduce the search space of query processing and the cost of index maintaining. Extensive experiments show that our algorithms are efficient and effective for on-line reverse skyline query.
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