Ajax is an important approach for improving rich interactivity between web server and end users during Web 2.0 eras. At the same time, AJAX web pages can not be indexed by search engines due to its asynchronous loadin...
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What-if analysis can provide more meaningful information than classical OLAP. Multi-scenario hypothesis based on historical data needs efficient what-if data view support. In general, delta table for what-if analysis ...
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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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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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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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Broadcasting/Multicasting problems have been well studied in wireless ad hoc networks. However, only a few approaches take into account the low interference and energy efficiency as the optimization objective simultan...
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ISBN:
(纸本)9781424451142
Broadcasting/Multicasting problems have been well studied in wireless ad hoc networks. However, only a few approaches take into account the low interference and energy efficiency as the optimization objective simultaneously. In this paper, we study the interference and power constrained broadcast/multicast and the delay-bounded interference and power constrained broadcast/multicast routing problems in wireless ad hoc networks using directional antennas. We propose an approximation and a heuristic algorithm for the two problems, respectively. Importantly, motivated by the study of above optimization problems, we propose approximation schemes for two multi-constrained directed Steiner tree problems, respectively. Broadcast/Multicast message by using the trees found by our algorithms tend to have less channel collisions and higher network throughput. The theoretical results are corroborated by simulation studies.
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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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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Traditional Web database cache techniques have a major disadvantage, namely poor data freshness, because they employ an asynchronous data refresh strategy. A novel Web database cache, DB Facade, is proposed in this pa...
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Traditional Web database cache techniques have a major disadvantage, namely poor data freshness, because they employ an asynchronous data refresh strategy. A novel Web database cache, DB Facade, is proposed in this paper. DB Facade uses a main memory database to cache result sets of previous queries for subsequent reusing. Updates on backend database system are managed by delta tables, and then propagated to Web database cache in a near real-time manner, hence guarantee the freshness of data. DB Facade off loads query burden from backend database systems, and exploits the power of main memory database system to boost query performance. TPC-W testing result shows that the system's performance increases by about 17 percent.
The existing code injection attack defense methods have some deficiencies on performance overhead and effectiveness. In order to ensure the system performance, we propose a method that uses system call randomization t...
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ISBN:
(纸本)9781424442232
The existing code injection attack defense methods have some deficiencies on performance overhead and effectiveness. In order to ensure the system performance, we propose a method that uses system call randomization to counter code injection attacks based on instruction set randomization idea. An injected code would perform its actions with system calls. System call randomization on operating system level will prevent the injected code from executing correctly. Moreover, with an extended compiler, our method can perform source code randomization during compiling and implement binary executable files randomization by feature matching. The experiments show that our method can effectively counter variety code injection attacks with low overhead.
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