This paper combines computational intelligence tools: neural network, fuzzy logic, and genetic algorithm to develop a data mining architecture (NFGDM), which discovers patterns and represents them in understandable forms. In the NFGDM, input data are preprocessed by fuzzification, the preprocessed data of input variables are then used to train a radial basis probabilistic neural network to classify the dataset according to the classes considered. A rule extraction technique is then applied in order to extract explicit knowledge from the trained neural networks and represent it in the form of fuzzy if\|then rules. In the final stage, genetic algorithm is used as a rule\|pruning module to eliminate those weak rules that are still in the rule bases. Comparison with some known neural network classifier, the architecture has fast learning speed, and it is characterized by the incorporation of the possibility information into the consequents of classification rules in human understandable forms. The experiments show that the NFGDM is more efficient and more robust than traditional decision tree method.
There exists an inherent difficulty in the original algorithm for the construction of Dwarf, which prevents it from constructing true Dwarfs. We explained when and why it introduces suffix redundancies into the Dwarf structure. To solve this problem, we proposed a completely new algorithm called PID. It bottom-up computes partitions of a fact table, and inserts them into the Dwarf structure. If a partition is an MSV partition, coalesce its sub-Dwarf; otherwise create necessary nodes and cells. Our performance study showed that PID is efficient. For further condensing of Dwarf, we proposed Condensed Dwarf, a more com- pressed structure, combining the strength of Dwarf and Condensed Cube. By eliminating unnecessary stores of “ALL” cells from the Dwarf structure, Condensed Dwarf could effectively reduce the size of Dwarf, especially for Dwarfs of the real world, which was illustrated by our experiments. Its query processing is still simple and, only two minor modifications to PID are required for the construction of Condensed Dwarf.
