In this paper, we propose a content-based publish/subscribe (pub/sub) framework that delivers matching content to subscribers in their desired format. Such a framework enables the pub/sub system to accommodate richer content formats including multimedia publications with image and video content. In our proposed framework, users (consumers) in addition to specifying their information needs (subscription queries), also specify their profile which includes the information about their receiving context which includes characteristics of the device used to receive the content (e.g., resolution of a PDA used by a consumer). The pub/sub system besides being responsible for matching and routing the published content, also becomes responsible for converting the content into the suitable format for each user. Content conversion is achieved through a set of content adaptation operators (e.g., image transcoder, document translator, etc.). We study algorithms for placement of such operators in heterogeneous pub/sub broker overlay in order to minimize the communication and computation resource consumption. Our experimental results show that careful placement of operators in pub/sub overlay network results in significant cost reduction.
Existing pub/sub systems have concentrated on providing efficient dissemination service for simple publication formats such as numerical content.
The receivers unable receive the content, if it is other format which is not supporting to them. Therefore the file content download rating will be decreased.
In proposed system, we introduced customized content dissemination system, where content is only delivered to receivers that have requested it and in their desired format.
We proposed operator placement algorithms on top of DHT-based pub/sub framework to customize content format such that dissemination cost, which we defined as a linear function of customization (computing) and transmission (communication) costs, is minimized.
We formally defined the problem proposed approaches to use estimated dissemination tree and take into account broker overlay heterogeneity and concurrent publications effect.
In our proposed framework, users (consumers) in addition to specifying their information needs (subscription queries), also specify their profile which includes the information about their receiving context which includes characteristics of the device used to receive the content (e.g., resolution of a PDA used by a consumer).
- Login and redirect
- Client Registration
- Rendezvous storage
- Rendezvous Algorithm
- Pub/Sub contents