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We consider (unbounded) Timed Petri Nets (TPNs) where each token is equipped with a real-valued clock representing the “age” of the token. Each arc in the net is provided with a subinterval of the natural numbers, restricting the ages of the tokens travelling the arc. We apply a methodology developed in [AN00], based on the theory of better quasi orderings(More)
We consider verification of safety properties for concurrent real-timed systems modelled as timed Petri nets, by performing symbolic forward reachability analysis. We introduce a formalism, called region generators for representing sets of markings of timed Petri nets. Region generators characterize downward closed sets of regions, and provide exact(More)
During the past two years, Massive Open Online Courses (MOOCs) have created wide interest in the academic world raising both enthusiasm for new opportunities for universities and many concerns for the future of university education. The discussion has mainly appeared in non-scientific forums, such as magazine articles, columns and blogs, making it difficult(More)
Massive Open Online Courses (MOOCs) have recently become a hot topic in the academic world, launching a wide ranging discussion on a number of issues. In this research, we surveyed academics' awareness, attitudes, perceptions, and experiences of MOOCs. We received responses from 236 academics from 23 countries, who were working in different roles such as(More)