Abstract: The main strengths of k-means clustering, the most widely used clustering technique for recommender systems, is its simplicity and ease of applicability to practical problems. However, k-means clustering suffers from the drawbacks of falling in local optima and the quality of clusters is largely dependent on the initial cluster centers. An important contribution of this paper is a hybrid k–means clustering approach to recommender systems that combines ‘outside the box’ recommendation ability of collaborative filtering with kmeans clustering and Genetic Algorithms. In this approach, genetic algorithm operators are used to pick up appropriate initial seeds for k-means clustering. This helps in improving cluster quality, thereby suggesting a new approach to recommender systems.

• Publication Date: 03-Jun-2011
• DOI: 10.15224/978-981-07-1847-3-1027
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Abstract: In this paper, we have analyzed the impact of laserspectral width and differential delay due to chromatic dispersion, incorporating dual-electrode Mach–Zehnder modulator (DEMZM), in radio-over-fiber(RoF) transmission system and results have been obtained. The results are calculated for 10 to 30 Km optical single side band (OSSB)–RoF transmission system by varying the laser line width. RoF system with OSSB has been used as it is tolerable for power degradation due to a chromatic fiber- dispersion, through a standard single-mode fiber (SSMF) carried by a continuous wave (CW) laser at 1550 nm of laser-spectral width varying from 100MHz to 650 MHz with CW power of 10mW that modulates a single RF channel of 30GHz. It has been found that deployment of lasers with lower spectral width will help the telecom industry to reduce the designing cost of RoF communication systems.

• Publication Date: 03-Jun-2011
• DOI: 10.15224/978-981-07-1847-3-1027
• Views: 0
• Downloads: 0