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Biblioteca Digital do IPB (53.442 recursos)

A Biblioteca Digital do IPB, tem por objectivo divulgar e permitir o livre acesso à produção científica produzida pela comunidade académica, promovendo a integração, partilha e a visibilidade da informação científica e garantindo a preservação da memória intelectual do Instituto Politécnico de Bragança.

DE - Livros e Capítulos de Livros

Mostrando recursos 1 - 20 de 25

  1. Towards self-organized service-oriented multi-agent systems

    Leitão, Paulo
    The demand for large-scale systems running in complex and even chaotic environments requires the consideration of new paradigms and technologies that provide flexibility, robustness, agility and responsiveness. Multiagents systems is pointed out as a suitable approach to address this challenge by offering an alternative way to design control systems, based on the decentralization of control functions over distributed autonomous and cooperative entities. However, in spite of their enormous potential, they usually lack some aspects related to interoperability, optimization in decentralized structures and truly self-adaptation. This paper discusses a new perspective to engineer adaptive complex systems considering a 3-layer framework integrating several...

  2. Adaptive multi-agent system for a washing machine production line

    Rodrigues, Nelson; Pereira, Arnaldo; Leitão, Paulo
    This paper describes the implementation of a multi-agent system in a real industrial washing machine production line aiming to integrate process and quality control, allowing the establishment of feedback control loops to support adaptation facing condition changes. For this purpose, the agent-based solution was implemented using the JADE framework, being the shared knowledge structured using a proper ontology, edited and validated in Protégé and posteriorly integrated in the multi-agent system. The solution was intensively tested using historical real production data and it is now being installed in the real production line. The preliminary results confirm the initial expectations in terms...

  3. Structural self-organized holonic multi-agent manufacturing system

    Barbosa, José; Leitão, Paulo; Adam, Emmanuel; Trentesaux, Damien
    Worldwide systems are increasingly growing into unprecedented complexity levels. This increase of system complexity has to be tackled with new control approaches, where decentralization is playing an important role and particularly the Multi-Agent Systems and Holonic Systems. Despite the benefits of this distribution, new problems arise such as the need for entities coordination. This paper proposes an innovative holonic multi-agent system architecture, named ADACOR2, which sets foundation on the already proved ADACOR ar-chitecture. This new control architecture is empowered by a two vector self-organization, called behavioural and structural self-organization. This paper de-scribes the structural self-organization vector, particularizing the need for...

  4. Holonic recursiveness with multi-agent system technologies

    Suarez, Sonia; Leitão, Paulo; Adam, Emmanuel
    Recursive Systems are often needed or recommended for automatically deploy or build a software system composed of multiple entities on a large network, or on distributed locations, without a central control. We use the recursive definitions proposed in holonic systems, as the recursiveness is an elemental structural property of their structure. Holonic systems are used to be implemented using MAS technologies (platforms) on the basis of the shared functional properties of autonomy and cooperation of agents and holons. This paper discusses the adequacy of the actual MAS technologies for holonic recursiveness implementation. A comparison of MAS platforms is done through a framework that will...

  5. Multi-agent system for on-demand production integrating production and quality control

    Leitão, Paulo; Rodrigues, Nelson
    Multi-agent systems is being pointed as particularly suited to design and engineer a new class of control systems to operate at the factory plants addressing the current requirements of modularity, flexibility and re-configurability. This paper introduces the main principles of a multi-agent system approach to support the integration of production and quality control processes in washing machines production lines that is being developed under the EU FP7 GRACE project.

  6. Recent developments and future trends of industrial agents

    Leitão, Paulo; Vrba, Pavel
    The agent technology provides a new way to design and engineer control solutions based on the decentralization of control over distributed structures, addressing the current requirements for modern control systems in industrial domains. This paper presents the current situation of the development and deployment of agent technology, discussing the initiatives and the current trends faced for a wider dissemination and industrial adoption, based on the work that is being carried out by the IEEE IES Technical Committee on Industrial Agents.

  7. Industrial agent technology

    Bratukhin, Aleksey; Peña, Yoseba; Leitão, Paulo; Unland, Rainer
    The conventional centralized, rigid information systems cannot serve the demands of modern (manufacturing) industry adequately any longer. In order to stay competitive, industry needs to be highly flexible, with shorter job sizes, variable product portfolios, and always changing shop floors. Although centralized approaches can in the meantime provide highly sophisticated and efficient scheduling solutions, the requirements imposed by novel manufacturing trends renders centralized control systems more and more unfeasible (cf. [8]). Against this background, multi-agent based industrial information systems seem to be a promising and natural alternative. They provide decentralized architecture, modularity, robustness, and adaptability to changes (cf. [9]). Moreover, the evolution of industry in the previous decades...

  8. Hybrid framework to image segmentation

    Monteiro, Fernando C.
    Indexado ISI

  9. Region and graph-based motion segmentation

    Monteiro, Fernando C.; Campilho, Aurélio
    Indexado ISI

  10. A project of speech input and output in an e-commerce application

    Freitas, D.; Moura, António; Braga, Daniela; Ferreira, Helder; Teixeira, João Paulo; Barros, Maria João; Gouveia, Paulo D.F.; Latsch, Vagner
    The present paper describes the work done during the last year in the development of European Portuguese (EP) speech recognition and synthesis channels for an Internet e-commerce application. The objective of this work was to develop the appropriate speech input and output, to enable the user to more comfortably use an e-commerce web site issuing commands and options under guidance of a menu system. The speech interface operation guidelines are briefly described in their principles and resulting specifications for the speech channels, namely, menu structure and operation dynamics, and in the following, the system software approach and the speech recognition...

  11. Performance evaluation of image segmentation

    Monteiro, Fernando C.; Campilho, Aurélio
    In spite of significant advances in image segmentation techniques, evaluation of these methods thus far has been largely subjective. Typically, the effectiveness of a new algorithm is demonstrated only by the presentation of a few segmented images that are evaluated by some method, or it is otherwise left to subjective evaluation by the reader. We propose a new approach for evaluation of segmentation that takes into account not only the accuracy of the boundary localization of the created segments but also the under-segmentation and over-segmentation effects, regardless to the number of regions in each partition. In addition, it takes into...

  12. Spectral methods in image segmentation: a combined approach

    Monteiro, Fernando C.; Campilho, Aurélio
    Indexado ISI

  13. Experimental validation of ADACOR holonic control system

    Leitão, Paulo; Restivo, Francisco
    In the last years, several manufacturing control architectures using emergent paradigms and technologies, such as multi-agent and holonic manufacturing systems, have been proposed to address the challenge of developing control systems capable of handling certain types of disturbances at the factory level. One of these holonic architectures is ADACOR, which integrates a set of paradigms and technologies for distributed manufacturing systems complemented by formal modelling techniques, to achieve a flexible and adaptive holonic/collaborative control architecture. The results obtained in the first experiments using the ADACOR architecture are presented in this paper, and also compared to the results produced by other...

  14. A manufacturing cell integration solution

    Leitão, Paulo; Machado, José; Lopes, José
    This paper intents to describe the work of integration developed in the metalwork manufacturing cell of CCP (Centro de CIM do Porto). It focus the manufacturing cell philosophy, the structure of the cell controller, and the way integration was done using the MMS communication standard. The present work was developed at CCP as a part of the ESPRIT 5629 Project, conclued in October 1995.

  15. A cell controller architecture solution: description and analysis of performance and costs

    Quintas, António; Leitão, Paulo
    Indexado ISI

  16. A holonic control approach for distributed manufacturing

    Leitão, Paulo; Restivo, Francisco
    Nowadays, manufacturing systems are complex and often chaotic environments, being collated with customer satisfaction, products shorter life cycle and new e-business trends, becoming the design of manufacturing control applications a complex and hard task. As the traditional control approaches present serious problems to handle simultaneously the distribution of functions, global production optimisation, reaction to disturbances and reconfiguration, it is necessary to introduce new concepts and technologies that support the new intelligent manufacturing control systems. The paper introduces an innovative holonic manufacturing control architecture to face some of these unsolved problems by supporting an increase of flexibility and an agile reaction...

  17. Holonic manufacturing control: a practical implementation

    Leitão, Paulo; Casais, Francisco; Restivo, Francisco
    Indexado ISI

  18. A holonic approach to dynamic manufacturing scheduling

    Leitão, Paulo; Restivo, Francisco
    Indexado ISI

  19. Foundations for a core ontology of manufacturing

    Borgo, Stefano; Leitão, Paulo
    An initial fragment of a core ontology for the manufacturing domain is presented and motivated. It consists of an ontological classification of ADACOR concepts according to the DOLCE foundational ontology. The ontology is conceptually transparent and semantically explicit thus suitable for information communication, sharing, and retrieval. The system here described considers entities performing the manufacturing scheduling and control operations only.

  20. Towards autonomy, self-organisation and learning in holonic manufacturing

    Leitão, Paulo; Restivo, Francisco
    This paper intends to discuss self-organisation and learning capabilities in autonomous and cooperative holons that are part of a holonic manufacturing control system. These capabilities will support the dynamic adaptation of the manufacturing control to the manufacturing evolution and emergency, specially the agile reaction to unexpected disturbances.

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