We consider a class of queueing systems that consist of server pools in parallel and multiple customer classes. Customer service times are assumed to be exponentially distributed. We study the asymptotic behavior of these queueing systems in a heavy traffic regime that is known as the Halfin and Whitt many-server asymptotic regime. Our main contribution is a general framework for establishing s...

In this paper, we present a heuristic approach for finding errors and possible improvements in business process models. First, we translate the information that is included in a model into a set of Prolog facts. We then search for patterns which are related to a violation of the soundness property, bad modeling style or otherwise give raise to the assumption that the model should be improved. B...

An input and output model is used for the development of a model based predictive control framework for linear model structures. Diierent MPC algorithms which are based on linear state space models or linear polynomial models t into this framework. A new identiication horizon is introduced in order to represent the past.

Formal specification languages are traditionally supported by theorem provers, but recently model checkers have proven to be useful tools. In this paper we present Eboc, an explicit state model checker for Event-B. Eboc is based on lazy techniques that allow it to fairly perform an exhaustive state space search without bounding the size of the sets used in the specification. We describe the imp...

Directed model checking is a well-established technique to tackle the state explosion problem when the aim is to find error states in large systems. In this approach, the state space traversal is guided through a function that estimates the distance to nearest error states. States with lower estimates are preferably expanded during the search. Obviously, the challenge is to develop distance fun...

We survey existing approaches to the formal verification of statecharts using model checking. Although the semantics and subset of statecharts used in each approach varies considerably, along with the model checkers and their specification languages, most approaches rely on translating the hierarchical structure into the flat representation of the input language of the model checker. This makes...

Model checking agent programs is a challenge and it is still a question which approaches can suitably be applied to effectively model check such programs. We present a new approach to explicit-state, onthe-fly model checking for agent programs. In this approach we use the agent program interpreter for generating the state space. A model checker is built on top of this interpreter by implementin...

State space explosion is the hardest challenge to the effective application of model checking methods. We present a new technique for achieving drastic state space reductions that can be applied to a very wide range of concurrent systems, namely any system specified as a rewrite theory. Given a rewrite theory R = (Σ,E,R) whose equational part (Σ,E) specifies some state predicates P , we identif...

New method for the state space representation of filters based on the companion form technique has been proposed. It is useful for synthesis of log domain filters. For state space representation of a log domain filter, it is very important to have almost equal coefficients of the state space equations since these coefficients are proportional to currents or voltages of the designed device. The ...

The sequential circuit state space diameter problem is an important problem in sequential verification. Bounded model checking is complete if the state space diameter of the system is known. By unrolling the transition relation, the sequential circuit state space diameter problem can be formulated as an evaluation for satisfiability of a Quantified Boolean Formula (QBF). This has prompted resea...