A Formal Framework For Multi-Party Business Protocols (Revision of CentER DP 2008-79)

Enterprise-class information systems based on the principles of Service Oriented Architecture comprise large numbers of long-running, highly dynamic complex end-to-end service interactions, called conversations, based on message exchanges that typically transcend several organizations and span several geographical locations. Conversations in service-based systems can be described using business protocols that are formal notations specifying the timed message exchanges among participants in a conversation from a local point of view (orchestrations) or global (choreographies). In this work we introduce a formal framework based on Deterministic Finite Automata enriched with temporal constraints to describe multi-party business protocols. We also explore the notion of multi-party business protocol soundness and show how it is possible to execute a multi-party protocol consistently in a completely distributed manner and at the same time ensure the progression of the execution (i.e. no “deadlocks”).service oriented architecture;message exchange patterns business protocols;orchestrations;choreographies;soundness

On Global Types and Multi-Party Session

Global types are formal specifications that describe communication protocols in terms of their global interactions. We present a new, streamlined language of global types equipped with a trace-based semantics and whose features and restrictions are semantically justified. The multi-party sessions obtained projecting our global types enjoy a liveness property in addition to the traditional progress and are shown to be sound and complete with respect to the set of traces of the originating global type. Our notion of completeness is less demanding than the classical ones, allowing a multi-party session to leave out redundant traces from an underspecified global type. In addition to the technical content, we discuss some limitations of our language of global types and provide an extensive comparison with related specification languages adopted in different communities

Accented Body and Beyond: a Model for Practice-Led Research with Multiple Theory/Practice Outcomes

Dance has always been a collaborative or interdisciplinary practice normally associated with music or sound and visual arts/design. Recent developments with technology have introduced additional layers of interdisciplinary work to include live and virtual forms in the expansion of what Fraleigh (1999:11) terms ‘the dancer oriented in time/space, somatically alive to the experience of moving’. This already multi-sensory experience and knowledge of the dancer is now layered with other kinds of space/time and kinetic awarenesses, both present and distant, through telematic presence, generative systems and/or sensors. In this world of altered perceptions and ways of being, the field of dance research is further opened up to alternative processes of inquiry, both theoretically and in practice, and importantly in the spaces between the two

Resonances: The sound of performance

It is a hot summer night in August 2013, as the audience gathers near the entrance of the large Gray Hall at the south side of the former coal mine Göttelborn (Germany). The sun has set, and there is only the gray light of dusk in the performance space inside, streaming through the large glass façade, falling onto a small array of stones laid out on the floor. Additional light from a video projector streams over the stones, and a tiny figure of a dancer is seen crawling over rocks, moving in the strange, a-syncopated rhythm of jump cuts. Slowly the sound of rocks scratching against a stone surface begins to be heard, it will remain the only sound for a while, then Japanese instrumentalist Emi Watanabe steps into the empty space with her flute