GMSME: An Architecture for Heterogeneous Collaboration with Mobile Devices Sangyoon Oh 1, 2 , Sunghoon Ko 1 , Geoffrey C. Fox 1, 2 1 Community Grids Computing Laboratory, Indiana University, IN, USA 501 N. Morton Suites 224, Bloomington, IN 47404 2 Computer Science Department, Indiana University, IN, USA {ohsangy, suko, gcf}@indiana.edu Tel: 812-856-0751 Fax: 812-856-7972 Abstract: The importance of network-ready personal devices in collaborative systems is becoming apparent. The participants of a collaborative environment use mobile devices to overcome the physical constraint of using a conventional PC. However, the integration of disparate devices like mobile devices and PCs is difficult, because of the connectivity and the computing power limitations of a mobile device. We believe a dedicated middleware layer that supports universal access, event mapping, user management, and content adaptation is a great help to integrate mobile devices into the collaborative system. In this paper, we propose a ubiquitous computing environment architecture for a collaborative system called Garnet Message System Micro Edition (GMSME). This architecture provides the environment to resolve those issues and is designed efficiently considering the computing resource limitations of mobile devices. Key Words: collaboration, mobile, universal access, filtering, middleware 1. INTRODUCTION Collaborative systems enable people to communicate and cooperate remotely. The Garnet Collaborative system [1] [2] is a universal access collaboration environment, which uses the NaradaBrokering Event system [3] as a messaging system. In recent years the use of network-ready mobile devices like Personal Digital Assistants (PDAs) and Smart phones as client devices has emerged as a major focus in collaborative systems. The combination of personal devices with conventional PCs in the collaborative system makes a great impact on the degree of collaboration. For instance, the universal access model of the Garnet system is extendable to more general universal access through personal devices. But it is not an easy goal to achieve. In many projects aiming at such integration, the limitation of the personal devices in terms of the connectivity and computing power has been an unavoidable issue. Even though there are many improvements recently, personal devices still lack in computing resources. We claim that the middleware layer between the collaborative system and the mobile devices resolves this drawback by efficiently mapping event messages and adapting content of messages. The middleware layer is a NaradaBrokering node that filters shared events and reposts them to a different stream [4]. In this paper, we propose an extensible and scalable architecture that provides universal accessibility and efficient server side computing. To make the architecture concrete, we have implemented a version, called Garnet Message System Micro Edition (GMSME) on the Garnet Collaborative System. The basic design issues and requirements for GMSME as a middleware layer are discussed in detail in Section 3. We present the architecture overview in Section 4. 2. GARNET AND NARADABROKERING The Garnet collaboration system [5] supports distance education, collaborative computing and building electric communities. It provides rich features of collaboration such as a video conferencing with SIP VoIP [6] and H.323 and a shared export with SVG. With the experience of developing TANGO [7] and using commercial collaboration system, for instance WebEx [8], Centra [9], the Garnet system integrates synchronous and asynchronous collaboration systems that are based on the publish/subscribe mechanism. For publish/subscribe semantics, we build on the NaradaBrokering system, which is a Java Message Service (JMS) [10] compliant message brokering system. NaradaBrokering is an event brokering system designed to run on a large network of cooperating broker nodes. It was originally designed to provide uniform software multicast to support real-time collaboration linked by publish/subscribe. As noted above, it is JMS compliant and provides supports not only for JMS clients, but also peer-to-peer communication providing JXTA interactions. NaradaBrokering provides a