Publish/subscribe model is widely used in distributed systems for information dissemination among different entities. A publish/subscribe broker decouples these entities and increases scalability of a publish/subscribe system. Web service is a promising technology to integrate heterogeneous applications in different organizations across Internet using standard XML data format. It is an important building block of the emerging service-oriented architecture (SOA).;With the increasing demand for interactions among software applications in different organizations, the scope of publish/subscribe message dissemination is extended to the Internet scale. How to facilitate such an extension is a new challenge.;In this dissertation, I propose a scalable service-oriented model, layered publish/subscribe model (LPS), that separates different concerns in Internet-scale publish/subscribe systems into five layers. Two related systems are developed based on this model: WS-Messenger and OpenPS.;The WS-Messenger project addresses new challenges in Web service-based publish/subscribe brokering systems. It proposes a flexible and efficient mediation approach to reconcile conflicts among competing specifications in Web service-based publish/subscribe systems, namely WS-Eventing and WS-Notification. The mediation approach is based on a normalization-processing-customization (NPC) mediation model. WS-Messenger has been successfully applied to service-oriented scientific workflows in the LEAD (Linked Environments for Atmospheric Discovery) project. It addresses several practical problems to ease the deployment of event-driven systems, such as monitoring, debugging and firewall-blocked message delivering.;The OpenPS project explores how to create an Internet-scale sharable publish/subscribe brokering service for message dissemination across organization boundaries. It is designed to achieve all three dimensions of scalability (load scalability, geographic scalability and administrative scalability) without losing support for expressive subscriptions. Analogous to postal service, OpenPS broker networks act as third-party services that focus on efficient and scalable message distribution across different organizations. They work together with local publish/subscribe brokers within each organization to achieve economies of scale in Web-based publish/subscribe message brokering in wide-area networks. Experimental studies conducted on these two prototype systems validate the feasibility of the LPS model.
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