排序方式: 共有69条查询结果,搜索用时 15 毫秒
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As an important type of multidimensional preference query, the skyline query can find a superset of optimal results when there is no given linear function to combine values for all attributes of interest. Its processing has been extensively investigated in the past. While most skyline query processing algorithms are designed based on the assumption that query processing is done for all attributes in a static dataset with deterministic attribute values, some advanced work has been done recently to remove part of such a strong assumption in order to process skyline queries for real-life applications, namely, to deal with data with multi-valued attributes (known as data uncertainty), to support skyline queries in a subspace which is a subset of attributes selected by the user, and to support continuous queries on streaming data. Naturally, there are many application scenarios where these three complex issues must be considered together. In this paper, we tackle the problem of probabilistic subspace skyline query processing over sliding windows on uncertain data streams. That is, to retrieve all objects from the most recent window of streaming data in a user-selected subspace with a skyline probability no smaller than a given threshold. Based on the subtle relationship between the full space and an arbitrary subspace, a novel approach using a regular grid indexing structure is developed for this problem. An extensive empirical study under various settings is conducted to show the effectiveness and efficiency of our PSS algorithm. 相似文献
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一种适用于JPEG2000的高速MQ编码器的VLSI实现 总被引:6,自引:0,他引:6
MQ编码器对于无损的数据压缩是一种非常有效的方法 ,它已被 JPEG2 0 0 0标准所采用。但该编码算法复杂度高 ,执行速度慢。文中提出了一种基于动态流水的高性能 MQ编码器的 VLSI结构。为了获得高速处理能力 ,首先分析了 JPEG2 0 0 0标准中 MQ编码算法的软件流程 ,并对其进行了相应的修改以适应硬件实现 ,然后采用了“动态流水”技术 ,可以根据变化的运算量来实时地安排流水操作。本 MQ编码器结构经 Xilinx FPGA实现 ,处理速度可达约 0 .6 2 5bit/ cycle( 32 .83Mbit/ sec) 相似文献
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在Soc的测试规划时,考虑为避免在测试过程中出现热点以及测试过程中使热量均匀分布,基于建立的问题模型得到一系列的并行测试集合,再通过Bin-Packing算法构造测试规划,并进行全局的优化.对ITC'02测试用例的实验结果表明,该方法在牺牲一定的测试时间的情况下,有效地控制了在测试时芯片温度的升高,从而避免出现由热量引起的一系列问题. 相似文献
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复杂的数字系统中需要一个高速的外部接口,因此SoC系统中集成USB主机控制器必然会成为一种新的趋势,而软件驱动是其重要的组成部分.通过基于SRISC-I处理器的增强型USB主机控制器的研究,采用软硬件协同设计的方法,设计和实现了一种分层结构的USB主机控制器软件驱动程序.采用了基于EHCI协议的软硬件接口,支持控制、批量、中断、同步4种传输模式.传输描述符数据结构的灵活性极大地降低了硬件软件复杂性,也使得传输时可以最大程度的减小内存的平均访问次数.同时,由于采用动态内存管理技术,充分地提高了专用内存的利用效率.为了提高验证的效率和保证系统的可靠性,采用了一种基于事件驱动的软硬件协同验证结构,并在流片后进行了验证,成功的实现了对大容量存储设备的访存. 相似文献
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一种新型片上网络互连结构的仿真和实现 总被引:2,自引:0,他引:2
综合性能、硬件实现等方面考虑,提出一种基于片上网络的互连拓扑结构-层次化路由结构MLR(Multi-Layer Router).该结构通过层次化设计减小网络直径,具有良好的对称性和扩展性.网络建模仿真和硬件实现结果显示,在不同网络负载和不同IP核节点数的情况下,MLR与传统结构相比,在处理网络通信时,对于网络丢包率、通信延迟和网络吞吐量等网络性能参数均有最多50%-70%的提升;同时通过共享路由的方式,减少了超过20%的芯片面积和40%以上的动态功耗,有效降低了互连结构的硬件开销 相似文献
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Driven by the flourish of location-based services, trajectory search has received significant attentions in recent years. Different from existing studies that focus on searching trajectories with spati... 相似文献