Abstract
In recent years, the technologies of the network and the computer have developed enormously and the diverse devices such as PDAs, mobile phones, TVs and etc which are connected to the network with various ways such as wired or wireless interfaces. These diverse devices have been able to use the web contents, but some clients can not use the web contents directly because their capabilities differ from those of the web content provider’s expectation. For these clients, the content adaptation, called the transcoding, is needed. This transcoding transforms the size, quality, presentation style, and etc of the web resources to meet the capabilities of the clients. The main features of the transcoding can be summarized with two. First is that multiple versions exist for the same web content due to the diverse client demand. Second is that the transcoding is a very computational task. These two features of the transcoding bring many issues to design a transcoding system.
Key Terms in this Chapter
Public Data Storage: A storage on a proxy cache for the group of clients which are on the cooperative proxy caches.
Transcoding: Transform the size, quality, presentation style, etc., of objects to meet the capabilities of clients.
Home Proxy: A proxy which is responsible for a target object key.
Private Storage: A storage on a proxy cache for the clients which are only on this proxy cache.
Proxy Cache: A server which locates on the border of ISP or institution and helps the original server by intercepting the user request.
Node ID: A unique and hashed value to identify a node.
Object ID: A unique and hashed value to identify an object.