CLUSTERING OF THREAD POSTS IN ONLINE DISCUSSION FORUMS
Online discussion forums are considered a challenging repository for data mining tasks. Forums usually contain hundreds of threads, which in turn composed of hundreds, or even thousands, of posts. Clustering these posts potentially will provide better visualization and exploration of online threads. Moreover, clustering can be used for discovering outlier and off-topic posts. In this paper, we propose the Leaderbased Post Clustering (LPC), a modification to the Leader algorithm to be applied to the domain of clustering posts in threads of discussion boards. We also suggest using asymmetric pair-wise distances to measure the dissimilarity between posts. We further investigate the effect of indirect distance between posts, and how to calibrate it with the direct distance. In order to evaluate the proposed methods, we conduct experiments using artificial and real threads extracted from Slashdot and Ciao discussion forums. Experimental results demonstrate the effectiveness of the LPC algorithm when using the linear combination of direct and indirect distances, as well as using an averaging approach to evaluate a representative indirect distance.
Nayer Wanas- Researcher, CMIC
Dina Said- Research Assistant, CMIC
FAST STITCHING OF VIDEOS CAPTURED FROM FREELY MOVING DEVICES
We investigate the problem of efficient panoramic video construction based on time-synchronized input video streams. No additional constraints are imposed regarding the motion of the capturing video cameras. The presented work is, to the best of our knowledge, the first attempt to construct in real-time a panoramic video stream from input video streams captured by freely moving cameras. The main contribution is in proposing an efficient panoramic video construction algorithm that exploits temporal information to avoid solving the stitching problem fully on a frame by frame basis. We provide detailed experimental evaluation of different methodologies that employ previous frames stitching results, such as tracking interest points using optical flow and using areas of overlap to limit the search space for interest points. Our results clearly indicate that making use of temporal information in video stitching can achieve a significant reduction in execution time while providing a comparable effectiveness.
Motaz El-Saban-Researcher, CMIC
Ayman Kaheel, CMIC
Mostafa Izz,-Research Assistant, CMIC