انجمن کامپیوتر ایران

Blinded data mining is a branch of data mining technique which is focused on protecting user privacy. To mine sensitive data such as medical information, it is desirable to protect privacy and there is not worry about revealing personalized data. In this paper a new approach for blinded data mining is suggested. It is based on ontology and k-anonymity generalization method. Our method generalizes a private table by considering table fields’ ontology, so that each tuple will become k-anonymous and less specific to not reveal sensitive information. This method is implemented using protégé and java for evaluation.

This paper presents an efficient algorithm for adaptive binarization of degraded document images. Document binarization algorithms suffer from poor and variable contrast in document images. We propose a contrast independent binarization algorithm that does not require any parameter setting by user. Therefore, it can handle various types of degraded document images. The proposed algorithm involves two consecutive stages. At the first stage, independent of contrast between foreground and background, some parts of each character are extracted and in the second stage, the gray level of foreground and background are locally estimated. For each pixel, the average of estimated foreground and background gray levels is defined as threshold. After extensive experiments, the proposed binarization algorithm demonstrate superior performance against four well-know binarization algorithms on a set of degraded document images captured with camera.

Quantum Evolutionary Algorithm (QEA) is a novel optimization algorithm which uses a probabilistic representation for solution and is highly suitable for combinatorial problems like Knapsack problem. Fractal image compression is a well-known problem which is in the class of NP-Hard problems. Genetic algorithms are widely used for fractal image compression problems, but QEA is not used for this kind of problems yet. This paper uses a novel Functional Sized population Quantum Evolutionary Algorithm for fractal image compression. Experimental results show that the proposed algorithm has a better performance than GA and conventional fractal image compression algorithms.

A watermarking method in DCT domain is modified to achieve better imperceptibility. Particle Swarm Optimization (PSO) is used to find the best DCT coefficients for embedding the watermark sequence and the Structural Similarity Index is used as the fitness function in order to have a watermarked image with the best possible quality.

A model of episodic memory is derived to propose algorithms of text categorization with semantic space models. Performances of two algorithms are contrasted using textual material of the text-mining context ‘DEFT09’. Results confirm that the episodic memory metaphor provides a convenient framework to propose efficient algorithm for text categorization. One algorithm has already been tested with LSA. The present paper extends these algorithms to another model of Word Vector named Random Indexing.