Naijing Hu Yuan Luo Yingying Wang Adaptive Evolvement of Query Plan Based on Low Cost in Dynamic Grid Database. 411-415 2008 SNPD http://doi.ieeecomputersociety.org/10.1109/SNPD.2008.14 conf/snpd/2008 db/conf/snpd/snpd2008.html#HuLW08