Synchronous cooperative systems (SCS) bring
together users that are geographically distributed and connected
through a network to carry out a task. Examples of SCS include Tele-
Immersion and Tele-Conferences. In SCS, the coordination is the
core of the system, and it has been defined as the act of managing
interdependencies between activities performed to achieve a goal.
Some of the main problems that SCS present deal with the
management of constraints between simultaneous activities and the
execution ordering of these activities. In order to resolve these
problems, orderings based on Lamport’s happened-before relation
have been used, namely, causal, Ä-causal, and causal-total orderings.
They mainly differ in the degree of asynchronous execution allowed.
One of the most important orderings is the causal order, which
establishes that the events must be seen in the cause-effect order as
they occur in the system. In this paper we show that for certain SCS
(e.g. videoconferences, tele-immersion) where some degradation of
the system is allowed, ensuring the causal order is still rigid, which
can render negative affects to the system. In this paper, we illustrate
how a more relaxed ordering, which we call Fuzzy Causal Order
(FCO), is useful for such kind of systems by allowing a more
asynchronous execution than the causal order. The benefit of the
FCO is illustrated by applying it to a particular scenario of
intermedia synchronization of an audio-conference system.