Middleware technologies suchus CORBA or Juvu RMI huve proved their suitubility for "stundurd" clientserver applications. However, challenges fiom existing and new types of upplicutions, including support for multimediu, reul-time requirements und mobility seems to indicute the need for defining U new urchitecture for open distributed systems. The new urchitecture should be designed Ji-om the beginning with flexibility und uduptubility in mind. This can be achieved by defining un open engineering middleware plutjorm thut is run time conjguruble und ullows inspection und uduptution of the underlying components. This puper proposes U next generution middlewure urchitecture thut conforms to requirements us indicated ubove. This urchitecture is churucterised by being open, and uduptuble bused on the principle of reflection. The puper ulso reports on some existing reseurch prototypes with U focus towurds their suitubility us next generution middle wure.

Real-time group editing has been envisioned as an effective manner of collaboration. For years, operational transformation (OT) has been the standard concurrency control mechanism for real-time group editing, due to its potential for high responsiveness to local editing operations. OT algorithms are generally non-trivial to be error-free and are computation intensive. Recently, commutative replicated data types (CRDT) have appeared as an alternative to OT. The state-of-the-art OT and CRDT work still lacks the basic functionality found in single-user text editors. In particular, there is no published work that supports both string-wise operations and selective undo. This paper presents an approach that combines and extends OT and CRDT strengths. It is fully decentralized and supports string-wise editing operations and selective undo. Our performance study shows that it provides sufficient responsiveness to the end-users.

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Scalability, consistency and reliability are among the key requirements for orchestration of BPEL processes. In addition, system resources should be efficiently utilized. We present a fully decentralized approach to orchestration of BPEL processes that achieves high scalability and supports automatic process recovery. The approach is of continuation-passing style, where continuations, or the reminder of the executions, are passed along with asynchronous messages for process orchestration. Furthermore, we identify and address two consistency issues that are more challenging for decentralized orchestrations.

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