Adaptability in Multi-tier Information Systems

Multi-tier architectures are now the standard for advanced information systems where clients make calls to the web-server (presentation tier), the business logic (shopping card, purchasing, browsing, etc.) is implemented and embedded in the application server tier, and the database tier stores all critical data.

In the commercial world, J2EE, .NET, and CORBA are specifications for the middle-tiers of such multi-tier architectures. Application servers provide far reaching functionality and services that help in the development of information systems. Important services are various communication mechanisms (remote procedure calls, messaging systems, persistent queues, etc.), transaction management, security, access control, persistence, and many more.
The fact that application servers introduce an additional layer of complexity, and that both web and application servers use a wide range of new technology leaves us with many challenging problems.

Our research looks at several issues in regard to such multi-tier architectures: