I have just posted the Concurrency Column for the June 2008 issue of the BEATCS. It is an excellent survey paper entitled 20 Years of Modal and Mixed Specifications by Adam Antonik, Michael Huth, Kim G. Larsen, Ulrik Nyman and Andrzej Wasowski.
Modal transition systems are a variation on the classic model of transition systems where transitions come in two flavours: those that any refinement of the given specification must possess, and those that it may, but is not required to,
have. This model of computation was introduced about twenty years ago by Kim Guldstrand Larsen and Bent Thomsen. Since then, it has been the subject of investigation by several groups of researchers, and interest in this model and in its sibling that goes by the name of mixed specifications has grown over the last few years. In the light of the recent rapid growth in the research literature on modal and mixed specifications, and their applications, I thought that it was appropriate to devote an instalment of the Concurrency Column to a survey of recent results and open problems in the field. I am very happy to be in a position to offer the readers of the Concurrency Column this excellent overview paper by some of the prime movers in the development of the theory and applications of modal and mixed specifications. I trust that this piece will be of general interest, and I hope that it will entice several researchers to contribute to the on-going work on these models. Enjoy!
If you'd like to contribute a piece to the Concurrency Column, do write to me.