Abstract. newYAWL is a business process modelling language founded on the work ow patterns. It radically extends the YAWL o ering to provide holistic support for the control- ow, data and resource perspectives and allows business processes to be captured in su cient detail that they can be directly enacted. In order to ensure that business processes are executed in a deterministic way, newYAWL is based on formal foundations. This paper describes the approach taken to specifying the operational semantics for newYAWL based on Coloured Petri Nets. It discusses the development of the semantic model for newYAWL, which was undertaken using CPN Tools, and the experiences associated with developing a complete operational design for an o ering of this scale using formal techniques. 1

Abstract. The contribution of this paper is to present a model-based approach to requirements engineering for reactive systems, and more specifically to controllers. The approach suggests the creation of a CPN model based on several diagrams, for validating the functional requirements of the system under development. An automatic gas pump controller is used as case study. We propose a generic structure for the CPN model to address the modelling of the controller, the physical entities which the controller interacts with, and the human users that operate the system. The CPN modules for modelling the behaviour of the human users and the controller are instances of a generic module that is able to interpret scenario descriptions specified in CPN ML. 1

This paper reports on an exercise on constructing a visual animation layer for a behaviourally-intensive reactive system. We assume that the requirements of the system under consideration are described by use cases, and the behaviour of each use case is detailed by a collection of scenario descriptions. These use cases and scenarios are translated into a Coloured Petri Net (CPN) model, which is subsequently complemented with animation-specific elements. We describe how the CPN model must be structured to facilitate the animation process, and we present the supporting tools for creating the animation. We consider an elevator controller system as a case study, to demonstrate that a CPN model complemented with a visual animation layer constitutes a solid basis for addressing behavioural issues in an early phase of the development process, namely during the validation task.

Abstract. Traditional work ow systems focus on providing support for the control- ow perspective of a business process, with other aspects such as data management and work distribution receiving markedly less attention. A guide to desirable work ow characteristics is provided by the well-known work ow patterns which are derived from a comprehensive survey of contemporary tools and modelling formalisms. In this paper we describe the approach taken to designing the newYAWL work ow system, an o ering that aims to provide comprehensive support for the control- ow, data and resource perspectives based on the work ow patterns. The semantics of the newYAWL work ow language are based on Coloured Petri Nets thus facilitating the direct enactment and analysis of processes described in terms of newYAWL language constructs. As part of this discussion, we explain how the operational semantics for each of the language elements are embodied in the newYAWL system and indicate the facilities required to support them in an operational environment. We also review the experiences associated with developing a complete operational design for an o ering of this scale using formal techniques. 1

This manuscript addresses the creation of scenario-based models to reason about the behavior of existing industrial information systems. In our approach the system behavior is modeled in two steps that gradually introduce detail and formality. This manuscript addresses the first step, where text-based descriptions, in the form of structured rules, are used to specify how the system is or should be regulated. Those rules can be used to create behavioral snapshots, which are collections of scenario-based descriptions that represent different instances of the system behavior. Snapshots are specified in an intuitive and graphical notation that considers the elements from the problem domain and permit designers to discuss and validate the externally observable behavior, together with the domain experts. In the second step (not fully covered in this manuscript), the system behavior is formalized with an executable model. This formal model, which in our approach is specified using the Colored Petri Net (CP-nets) language, allows the system internal behavior to be animated, simulated, and optimized. The insights gained by experimenting with the formal model can be subsequently used for reengineering the existing system.

The contribution of this paper is to present a model-based approach to requirements engineering for reactive systems, and more specifically to controllers. The approach suggests the creation of a CPN model based on several diagrams, for validating the functional requirements of the system under development. An automatic gas pump controller is used as case study. We propose a generic structure for the CPN model to address the modelling of the controller, the physical entities which the controller interacts with, and the human users that operate the system. The CPN modules for modelling the behaviour of the human users and the controller are instances of a generic module that is able to interpret scenario descriptions specified in CPN ML.

Abstract. Traditional workflow systems focus on providing support for the control-flow perspective of a business process, with other aspects such as data management and work distribution receiving markedly less attention. A guide to desirable workflow characteristics is provided by the well-known workflow patterns which are derived from a comprehensive survey of contemporary tools and modelling formalisms. In this paper we describe the approach taken to designing the newYAWL workflow system, an offering that aims to provide comprehensive support for the control-flow, data and resource perspectives based on the workflow patterns. The semantics of the newYAWL workflow language are based on Coloured Petri Nets thus facilitating the direct enactment and analysis of processes described in terms of newYAWL language constructs. As part of this discussion, we explain how the operational semantics for each of the language elements are embodied in the newYAWL system and indicate the facilities required to support them in an operational environment. We also review the experiences associated with developing a complete operational design for an offering of this scale using formal techniques.

A scenario can be used to describe a possible instantiation of a given business use case and can be expressed for example as a list of steps written in natural language, or by an interaction diagram. This paper discusses how a collection of scenarios, all expressed as UML2 sequence diagrams, can be described for validation purposes by a single model, written in the Coloured Petri Nets (CPN) modelling language. Due to the support for parallelism given by the CPN language, the obtained CPN model can: (1) simultaneously execute several scenarios; and (2) elegantly represent the parallel activities inside a scenario. This twolevel parallelism is crucial during validation, since it allows one to detect problems that are only evident when several scenarios are in simultaneous execution and may affect each other. We exemplify our approach in a system that has a rich set of interactions with its users.

Abstract. newYAWL is a business process modelling language founded on the work ow patterns. It radically extends the YAWL o ering to provide holistic support for the control- ow, data and resource perspectives and allows business processes to be captured in su cient detail that they can be directly enacted. In order to ensure that business processes are executed in a deterministic way, newYAWL is based on formal foundations. This paper describes the approach taken to specifying the operational semantics for newYAWL based on Coloured Petri Nets. It discusses the development of the semantic model for newYAWL, which was undertaken using CPN Tools, and the experiences associated with developing a complete operational design for an o ering of this scale using formal techniques. 1