Coordinated Enroute Multimedia Object Caching in Transcoding Proxies for Tree Networks

作     者：Li, Keqiu Shen, Hong 

作者机构：Japan Adv Inst Sci & Technol Grad Sch Informat Sci Nomi Ishikawa 9231292 Japan Univ Sci & Technol China Dept Comp Sci & Technol Hefei 230026 Anhui Peoples R China 

出 版 物：《ACM TRANSACTIONS ON MULTIMEDIA COMPUTING COMMUNICATIONS AND APPLICATIONS》 (ACM多媒体计算通信应用汇刊)

年 卷 期：2005年第1卷第3期

页      面：289-314页

核心收录：

学科分类：0809[工学-电子科学与技术（可授工学、理学学位）] 08[工学] 0835[工学-软件工程] 0812[工学-计算机科学与技术（可授工学、理学学位）] 

主　　题：Algorithms Design Management Performance Web caching transcoding proxy multimedia object optimization problem Internet tree network 

摘      要：Transcoding is a promising technology that allows systems to effect a quality-versus-size tradeoff on multimedia objects. As audio and video applications have proliferated on the Internet, caching in transcoding proxies has become an important technique for improving network performance, especially in mobile networks. This article addresses the problem of coordinated enroute multimedia object caching in transcoding proxies for tree networks. We formulate this problem as an optimization problem based on our proposed model, in which multimedia object caching decisions are made on all enroute caches along the routing path by integrating both object placement and replacement policies and cache status information along the routing path of a request is used to determine the optimal locations for caching multiple versions of the same multimedia object. We propose an optimal solution using dynamic programming to compute the optimal locations. We also extend this solution to solve the same problem for several constrained cases, including constraints on the cost gain per node and on the number of versions to be placed. Our model is evaluated on different performance metrics through extensive simulation experiments. The implementation results show that our model significantly outperforms existing models that consider Web caching in transcoding proxies either on a single path or at individual nodes.