Abstract
In service-oriented systems, composition of services is required to build new, distributed and more complex services, based on the logic behavior of individual ones. This paper discusses the formal composition of Petri nets models used for the process description and control in service-oriented automation systems. The proposed approach considers two forms for the composition of services, notably the offline composition, applied during the design phase, and the online composition, related to the synchronization of Petri nets models on the fly. An experimental case study is used to illustrate the proposed composition approach. © 2010 IEEE.

Abstract
This paper introduces a novel method for the specification and selection of criteria-weighted operation modes for the orchestration of services in industrial automation using Petri nets. The objective is to provide to the internal decision support system of a service-oriented automation device or of another applicable computational system the capability to select the best path in a Petri net orchestration model considering different criteria to evaluate the quality of services, such as the time, energy efficiency and reliability. The transition-invariants obtained from the Petri net represent the set of possible modi operandi and these are then weighted with decision criteria. The result will be afterwards evaluated in order to select the optimal modus operandi to be executed by the device. Based on the experiments, this method permits the dynamic optimization of processes in real-time, considering available parameters from devices and other resources. © 2010 IEEE.

Abstract
The Virtual manufacturing concept is based on the use of computational resources during the design of products and manufacturing systems, reducing the ramp-up time to market and the costs for the system's design, operation and reconfiguration. Combined with emergent paradigms for manufacturing control, such as multi-agent systems and service-orientation principles, and using a formal language to describe the system behavior, e.g. Petri nets, a truly and complete virtual production environment is achieved. This paper discusses this powerful approach to the virtual design and production environment driven by formal models, allowing users to design and deploy collaborative and re-configurable automation applications in a faster and cost-effective fashion. A special attention is devoted to the process of migration from the virtual environment to the real world, aiming to reduce the transition time and increasing the efficiency of the process.

Abstract
The expected behavior of industrial automation systems can be defined and modeled, but since not every event is predicted at design time, additional care has to be taken during the operation to handle situations such as exceptions, failures and new production orders. Another remark is also the limitation of modeling languages used in the control to permit the intervention of higher grade decision mechanisms. This paper discusses the application of decision support system for Petri net based processes to control automation components and devices. The decision mechanisms are used for path planning, production scheduling and preventive maintenance, to support the description of processes in Petri nets formalism. As such, the same Petri nets designed for the control are also used as analytical information input to the decision support system and for the detection process options that require decision. The solution provides a dynamic complement to the static modeling and operational flexibility. Experiments were done in a real service-oriented industrial factory-cell to prove the specified approach.

Abstract
Service-oriented systems constitute a suitable approach for the development of modular, flexible and reconfigurable production systems, addressing the current requirements imposed by global markets. This paper focuses on the process control of Service-oriented production systems, whose behavior is regulated by the coordination of services that are available from distributed modular and collaborative control components. The proposed control is based on a kind of High-level Petri Nets tailored for the description, connection and synchronization of different concurrent processes. Several features can be distinguished by this approach, since its modularity, control reusability, flexibility and other valuable inherited characteristics from the proposed High-Level Petri Nets.

Abstract
Evolvable and collaborative production systems are becoming an emergent paradigm towards flexibility and automatic re-configurability. The reconfiguration of those systems requires the existence of distributed and modular control components that interact in order to accomplish control activities. This paper focuses on service-oriented production systems, which behavior is regulated by the coordination of services that are provided and required by control components with different roles. Internally, these components are independent of the implementations, but an internal modular and event based structure is presented. Individual control and interaction is achieved by using embedded or inter-service control processes for which High-Level Petri Nets are proposed. Supporting the predefined control, decision support systems are used to provide conflict resolution and other decision-making functions.