Alexander Serebrenik

Learn More
The research domain of process discovery aims at constructing a process model (e.g. a Petri net) which is an abstract representation of an execution log. Such a Petri net should (1) be able to reproduce the log under consideration and (2) be independent of the number of cases in the log. In this paper, we present a process discovery algorithm where we use(More)
Historically, mailing lists have been the preferred means for coordinating development and user support activities. With the emergence and popularity growth of social Q&A sites such as the StackExchange network (e.g., StackOverflow), this is beginning to change. Such sites offer different socio-technical incentives to their participants than mailing(More)
There are two kinds of approaches for termination analysis of logic programs: “transformational” and “direct” ones. Direct approaches prove termination directly on the basis of the logic program. Transformational approaches transform a logic program into a term rewrite system (TRS) and then analyze termination of the resulting TRS instead. Thus,(More)
Termination is an important and well-studied property for logic programs. However, almost all approaches for automated termination analysis focus on definite logic programs, whereas real-world Prolog programs typically use the cut operator. We introduce a novel pre-processing method which automatically transforms Prolog programs into logic programs without(More)
Online communities are flourishing as social meeting web-spaces for users and peer community members. Different online communities require different levels of competence for participants to join, and scattered evidence suggests that women can be overly under-represented. Moreover, anecdotal evidence of the Q&amp, A website Stack Overflow suggests that(More)
We consider nested nets, i.e. Petri nets in which tokens can be Petri nets themselves. We study the value semantics of nested nets rather than the reference semantics, and apply nested nets to model adaptive workflow, i.e. flexible workflow that can be modified during the execution. A typical domain with a great need for this kind of workflow is health(More)
Stack Overflow is a popular on-line programming question and answer community providing its participants with rapid access to knowledge and expertise of their peers, especially benefitting coders. Despite the popularity of Stack Overflow, its role in the work cycle of open-source developers is yet to be understood: on the one hand, participation in it has(More)
We study concurrent processes modelled as workflow Petri nets extended with resource constraints. We define a behavioural correctness criterion called soundness: given a sufficient initial number of resources, all cases in the net are guaranteed to terminate successfully, no matter which schedule is used. We give a necessary and sufficient condition for(More)