Extending LOTOS with time: A true concurrency perspective

An ongoing restandardisation activity is currently extending the OSI specification language LOTOS with quantitative time. We give an alternative perspective on this activity. We highlight a very simple but expressive timed LOTOS enhancement which is based on time intervals. The main point at which we depart from the standard approach to extending LOTOS with time, is that we employ a true concurrency semantics. We present a semantics based on a time extended bundle event structures. We give a full semantics for relating our timed LOTOS to timed bundle event structures. A fixed point theory is defined and finally, we describe how urgency can be supported in the language.