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Discussions and Conclusions

From the experimental results, different values of data dependency will cause the same

large itemsets, but different predictive effects. When w=1, the non-promising candidate sets

are predicted very well, but the promising candidate sets are predicted badly; and vice versa

for w=0. By default, we set w=0.5. If the data dependency relationships in transactions can be

well utilized, our method can improve the overall performance of finding large itemsets.

In our experiments, both the (n, p) algorithm and ours suffer from the inefficiency of

generating Ci++1 from Ci+. When there are many items in the dataset, e.g., 25 items in

D1~D6, and more levels of transactions to be considered, more computation is needed in both

algorithms. However, our method provides a more accurate approach for predicting itemsets

and obtains a better performance than the (n, p) algorithm, especially when p>2.

In this paper, we have presented a mining algorithm that combines the advantages of the

apriori and the (n, p) algorithm in finding large itemsets. As the (n, p) algorithm does, our

algorithm reduces the number of scanning datasets for finding p levels of large itemsets. A

new parameter that considers data dependency is included in our method for early filtering

out the itemsets that are possibly of lower supports and thus improves the computational

efficiency.

We also conclude that the three algorithms can compete with each other and gain the best

performance on different types of datasets. There need more studies on how to tune the

parameters, such as n, p, and transaction threshold in the (n, p) algorithm and w, t in ours,

before the mining task is performed.

Acknowledgement

The authors would also like to thank Mr. Tsung-Te in the department of information

management, Shu-Te University, Taiwan, for his help in conducting the experiments.

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