My main area of research is data-centric networking in the contexts of mobile distributed systems and middleware for the semantic web. Data-centric networking relies on content addressing instead of host (e.g., IP) addressing for participating nodes, thus providing network independence for applications.
Data-centric networking is particularly important for networks supporting mobile clients. In such networks, client applications want to receive data specific to them, regardless of where that data is located in the network. Network independence, through data-centric networking, makes it easier to develop robust mobile applications that are resilient to network dynamics.
Data-centric routing is fundamentally different from host-based routing because data is routed based on queries describing user's interest, rather than host addresses. As more and more applications depend on XML and RDF for data representation, there is a growing need for efficient data-centric routing protocols that can support a kind of query language expressiveness that is needed for routing XML/RDF data.
Middleware for Automation Applications in Sensor/Actuator Networks
We have developed a middleware system to address the challenge of in-network actuation for automation applications using embedded sensor/actuator technology. The middleware system combines a number of devices to create a declarative data flow management systems for in-network execution of distributed automation applications. [more]
The key features of the middleware are:
- A relational database-like system for resource constrained environments. The key features of the system are in-memory tables, queries with compile-time query plan generation and triggers. Relational model and declarative data manipulation using queries and triggers makes it easy to deal with complex conceptual model and the data flow management.
- A distributed data flow processor for resource constrained automation applications. The processors provides an SQL-like query language, shared query processing, distributed indexing and a data flow optimizer.
Mobility in Publish/Subscribe Systems
Publish/Subscribe interaction model provides a data-centric network abstraction for developing distributed applications. By allowing applications to specify data that they are interested in receiving by name, rather then by explicit network location, makes application independent of the underlying network transport. This makes writing distributed application much easier and simpler, since the applications do not need to know explicitly about network reconfiguration. In other words, publish/subscribe paradigm allows creation of application-level network virtualization. [more]
- Muthusamy, V., Petrovic, M., Jacobsen, H.-A.,
Effects of Routing Computations in Content-Based Routing Networks with Mobile Data Sources. In Proceedings of 11th Annual International Conference on Mobile Computing and Networking (MOBICOM). August 2005.
- Petrovic, M., Muthusamy, V., Jacobsen, H.-A.,
Content-Based Routing in Mobile Ad Hoc Networks. In Proceedings of 2nd International
Conference on Mobile and Ubiquitous Systems (Mobiquitous). July 2005.
- Muthusamy, V., Petrovic, M., Gao, D., Jacobsen, H.-A., Publisher Mobility in Distributed Publish/Subscribe Systems. In Proceedings of International Workshop on Distributed Event-Based Systems (DEBS). June 2005.
- Burcea, I., Jacobsen, H-A., de Lara, E., Muthusamy, V., Petrovic, M. Disconnected Operation in Publish/Subscribe Middleware. In Proceedings of IEEE International Conference on Mobile Data Management (MDM). January 2004.
Middleware for the Semantic Web
The main benefit of publish/subscribe communication model lies in the abstraction of addressing. In essence, pub/sub creates data-addressable networks. The goal of this project is to examine data-centric abstractions that would be considered useful for application development in the future. We used the emerging areas of distributed application development such as web service integration and collaboration as a guide to what would be considered useful for a number of applications. [more]
- Liu, H., Petrovic, M., Jacobsen, H.-A., Efficient and Scalable Filtering of Graph-based Metadata. To appear in Journal of Web Semantics. January 2006.
- Petrovic, M., Liu, H., Jacobsen, H.-A., CMS-ToPSS: Efficient Dissemination of RSS Documents. In Proceedings of 31st International Conference on Very Large Data Bases (VLDB). September 2005. (System demonstration)
- Petrovic, M., Liu, H., Jacobsen, H.-A., G-ToPSS: Fast Filtering of Graph-based Metadata. In Proceedings of 14th International World Wide Web Conference (WWW). May 2005. Best Paper Finalist.
- Burcea, I., Petrovic, M., Jacobsen, H-A. I know what you mean: semantic issues in Internet-scale publish/subscribe systems. In Proceedings of the First International Workshop on Semantic Web and Databases. September 2003
- Petrovic, M., Burcea, I., Jacobsen, H-A. S-ToPSS: Semantic Toronto Publish/Subscribe System. In Proceedings of 29th International Conference on Very Large Databases (VLDB). September 2003. (System demonstration)
Using TCP over Wireless Links
Congestion avoidance algorithms used in TCP were one of the main reasons for TCPs good performance in wired networks. However, the algorithms are also the main culprit of TCP's poor performance over wireless links. The problems stems from TCP's inability to distinguish packet losses due to congestion from those caused by wireless transmission errors. Consequently, congestion avoidance is invoked much more frequently than it needs to be causing TCP flows to experience low throughput. The purpose of this research was to study the effectiveness of using forward error correction to mask wireless transmission errors for soft real-time and bulk traffic in cellular as well as MANET environments.
- Petrovic, M, and Aboelaze, M. Performance of TCP/IP Under ad hoc IEEE802.11. In Proceedings of the 10th IEEE International Conference on Telecommunication (ICT). February 2003.
- Petrovic, M., Aboelaze, M. Improving TCP/IP Performance over Wireless IEEE 802.11 Link.In Proceedings of the International Conference on Wireless Networks (ICWN). June 2002.
- CSC2221 Theory of Distributed Systems (Vassos Hadzilacos and Sam Toueg)
- CSC2231 Mobile and Pervasive Computing (Eyal de Lara)
- CS856 Web Data Management (at University of Waterloo with M.Tamer Ozsu)
- ECE1771 Quality-of-Service Provisioning in Mobile Networks (Baochun Li)
- ECE1770 Trends in Middleware Systems (H.-Arno Jacobsen)
- ECE344 Operating Systems (Spring 2003, Spring 2004, Spring 2005, Fall 2005, Spring 2006)
- ECE242 Data Structures and Algorithms (Fall 2003)
- APS105 Computer Fundamentals (Fall 2004, Spring 2006)
All my research is done within middleware systems research group (MSRG) at University of Toronto. MSRG conducts research on content-based routing systems and aspect-oriented software architecture of middleware. Projects range from the design of data-centric routing protocols and query languages to aspect-oriented software architectures, focusing on information management in a wide range of environments starting from super-constrained sensor networks to pervasive environments to semantic web middleware. Professor Arno Jacobsen teaches a class, Trends in Middleware Systems (ECE1770), which introduces this research area.