Broadcast program generation for Webcasting

摘要

The advances in computer and communication technologies have made possible an ubiquitous computing environment were clients equipped with portable devices can send and receive data anytime and from anyplace. In such an asymmetric communication environment, data push has emerged as a very effective and scalable way to deliver information. Recently, the combination of push technology with the Internet and the Web [IEEE Trans. Comput. 50 (2001) 506, ACM/Kluwer Mobile Networks Appl. 7 (2002) 67] (referred to as Webcasting) has emerged “as a way out of the Web maze”. Any broadcast program employed for Webcasting must be able to scale to the large number of transmitted pages.We study the issue of creating hierarchical Webcasting programs. We propose a new algorithm, CascadedWebcasting, for the generation of Webcasting programs, scalable in terms of the number of items transmitted and able to produce programs very close to optimal. We give an analytic model of the time complexity of the proposed method and we present a performance evaluation of CascadedWebcasting and a detailed comparison with existing algorithms using synthetic as well as real data. The experiments show that the CascadedWebcasting has negligible execution time and achieves an average access delay very close to that of the optimal algorithm.