Im Seokjin, Choi JinTak
Department of Computer Engineering, Sungkyul University, 53, SungkyulDaehak-Ro, Manan-Gu,Anyang, Gyeonggi-Do 430-742, Korea.
Department of Computer Engineering, Incheon National University, 119 Academy-Ro, Yeonsu-Gu,Incheon 406-772, Korea.
Sensors (Basel). 2014 Jun 17;14(6):10619-43. doi: 10.3390/s140610619.
In the pervasive computing environment using smart devices equipped with various sensors, a wireless data broadcasting system for spatial data items is a natural way to efficiently provide a location dependent information service, regardless of the number of clients. A non-flat wireless broadcast system can support the clients in accessing quickly their preferred data items by disseminating the preferred data items more frequently than regular data on the wireless channel. To efficiently support the processing of spatial window queries in a non-flat wireless data broadcasting system, we propose a distributed air index based on a maximum boundary rectangle (MaxBR) over grid-cells (abbreviated DAIM), which uses MaxBRs for filtering out hot data items on the wireless channel. Unlike the existing index that repeats regular data items in close proximity to hot items at same frequency as hot data items in a broadcast cycle, DAIM makes it possible to repeat only hot data items in a cycle and reduces the length of the broadcast cycle. Consequently, DAIM helps the clients access the desired items quickly, improves the access time, and reduces energy consumption. In addition, a MaxBR helps the clients decide whether they have to access regular data items or not. Simulation studies show the proposed DAIM outperforms existing schemes with respect to the access time and energy consumption.
在使用配备各种传感器的智能设备的普适计算环境中，用于空间数据项的无线数据广播系统是一种自然的方式，可高效地提供位置相关信息服务，而不论客户端数量多少。非平坦无线广播系统可以通过在无线信道上比常规数据更频繁地传播首选数据项，来支持客户端快速访问他们的首选数据项。为了在非平坦无线数据广播系统中高效支持空间窗口查询的处理，我们提出了一种基于网格单元上的最大边界矩形（MaxBR）的分布式空中索引（简称为DAIM），它使用MaxBR来过滤无线信道上的热门数据项。与现有索引在广播周期中以与热门数据项相同的频率重复靠近热门项的常规数据项不同，DAIM使得在一个周期中仅重复热门数据项成为可能，并缩短了广播周期。因此，DAIM帮助客户端快速访问所需项，改善了访问时间并降低了能耗。此外，MaxBR帮助客户端决定他们是否必须访问常规数据项。仿真研究表明，所提出的DAIM在访问时间和能耗方面优于现有方案。
