Since the eruption of the recent global financial crisis, major countries have been pushing forward structural reforms with science and technology （S＆T） innovation at the heart. Since taking office, US President Do...Since the eruption of the recent global financial crisis, major countries have been pushing forward structural reforms with science and technology （S＆T） innovation at the heart. Since taking office, US President Donald Trump has adopted an ＂America First＂ strategy but has yet to specify a clear S＆T innovation policy. However, Trump＇s current policies have already affected S＆T innovation and his planned budget cuts will impact US growth potentials. Compared with the US, China is steadily implementing its innovation-driven development strategy with significant improvement in S＆ T innovation that increasingly supports economic growth. To spur future economic growth, China should steadfastly follow its S＆T innovation strategy, promote the utilization of S＆T innovation results, boost its economic growth potentials and make the most of global innovation resources.展开更多
By analyzing the existing prefix-tree data structure, an improved pattern tree was introduced for processing new transactions. It firstly stored transactions in a lexicographic order tree and then restructured the tre...By analyzing the existing prefix-tree data structure, an improved pattern tree was introduced for processing new transactions. It firstly stored transactions in a lexicographic order tree and then restructured the tree by sorting each path in a frequency-descending order. While updating the improved pattern tree, there was no need to rescan the entire new database or reconstruct a new tree for incremental updating. A test was performed on synthetic dataset T1014D100K with 100 000 transactions and 870 items. Experimental results show that the smaller the minimum sup- port threshold, the faster the improved pattern tree achieves over CanTree for all datasets. As the minimum support threshold increased from 2% to 3.5%, the runtime decreased from 452.71 s to 186.26 s. Meanwhile, the runtime re- quired by CanTree decreased from 1 367.03 s to 432.19 s. When the database was updated, the execution time of im- proved pattern tree consisted of construction of original improved pattern trees and reconstruction of initial tree. The experiment results showed that the runtime was saved by about 15% compared with that of CanTree. As the number of transactions increased, the runtime of improved pattern tree was about 25% shorter than that of FP-tree. The improved pattern tree also required less memory than CanTree.展开更多
文摘Since the eruption of the recent global financial crisis, major countries have been pushing forward structural reforms with science and technology （S＆T） innovation at the heart. Since taking office, US President Donald Trump has adopted an ＂America First＂ strategy but has yet to specify a clear S＆T innovation policy. However, Trump＇s current policies have already affected S＆T innovation and his planned budget cuts will impact US growth potentials. Compared with the US, China is steadily implementing its innovation-driven development strategy with significant improvement in S＆ T innovation that increasingly supports economic growth. To spur future economic growth, China should steadfastly follow its S＆T innovation strategy, promote the utilization of S＆T innovation results, boost its economic growth potentials and make the most of global innovation resources.
基金Supported by National Natural Science Foundation of China (No.50975193)Specialized Research Fund for Doctoral Program of Higher Education of China (No.20060056016)
文摘By analyzing the existing prefix-tree data structure, an improved pattern tree was introduced for processing new transactions. It firstly stored transactions in a lexicographic order tree and then restructured the tree by sorting each path in a frequency-descending order. While updating the improved pattern tree, there was no need to rescan the entire new database or reconstruct a new tree for incremental updating. A test was performed on synthetic dataset T1014D100K with 100 000 transactions and 870 items. Experimental results show that the smaller the minimum sup- port threshold, the faster the improved pattern tree achieves over CanTree for all datasets. As the minimum support threshold increased from 2% to 3.5%, the runtime decreased from 452.71 s to 186.26 s. Meanwhile, the runtime re- quired by CanTree decreased from 1 367.03 s to 432.19 s. When the database was updated, the execution time of im- proved pattern tree consisted of construction of original improved pattern trees and reconstruction of initial tree. The experiment results showed that the runtime was saved by about 15% compared with that of CanTree. As the number of transactions increased, the runtime of improved pattern tree was about 25% shorter than that of FP-tree. The improved pattern tree also required less memory than CanTree.
