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- Hasan, Baha, 1977-
(författare)
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An Ontological Approach to support Knowledge Sharing between Product Design and Assembly Process Planning (APP)
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modern manufacturing organizations have to cope with several critical issues arising from the need for mass customization such as short product life-cycles, an increasing number of product variants and frequently changing customer requirements. One of the main factors that could aid overcoming those challenges is the use of information and communication technology (ICT) applications over a collaborative manufacturing environment, in which all stakeholders share and exchange knowledge across different manufacturing domains and applications. However, the use of ICT applications over a collaborative manufacturing environment is limited at the domain level by semantic conflicts arising from the use of different ways to describe the same objects and facts arising from different conceptualizations. Similarly, ICT usage is limited on the application level by interoperability problems arising from diverse heterogeneity between different ICT applications and tools.This research presents a semantic approach to support knowledge sharing within the assembly domain. More specifically, this research is focusing on capturing and sharing assembly design knowledge and integrating the assembly design domain and the Assembly Process Planning (APP) domain. Assembly design and APP are very important engineering domains for successful manufacturing system design, which requires an efficient collaborative environment for best utilization of the assembly resources. However, though these domains represent different perspectives in understanding of the same concepts, both domains use different software applications, which might cause interoperability issues.In this thesis, a novel integration approach has been proposed; this approach is composed of two stages: the first stage includes modelling and recognition of assembly knowledge semantics from SolidWorks (SW) CAD software by using SolidWorks’ Application Programmable Interface (SW-API). The second stage includes sharing the recognized assembly knowledge semantics by using a knowledge-based system in the form of a three-layer ontology architecture which provides a common semantic base to support knowledge sharing across assembly design and APP both on the domain and the application level. Each ontology layer shares a set of concepts from the most generic level to the most specialized level. The foundation ontology layer represents the general key concepts in the assembly design and APP domains. More specialized assembly design concepts and APP concepts are represented both in the domain ontology layer, and the application ontology layer. In the latter, concepts related to SolidWorks CAD software and to assembly robotic devices are represented.
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| 2. |
- Akillioglu, Hakan, 1983-
(författare)
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Evolvable Production Systems: Demand Responsive Planning
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Dynamic and unforeseeable characteristic of the current market and production environment is not feasible to be met through pre-set parameters being dependent on the predictions. Handling this matter requires to keep focus on production system adaptability. Evolvable Production System has achieved fully system reconfigurability through process oriented modularity and multi agent based distributed control system architecture. One of the essential enhancements provided by EPS on the shop floor is achieving minimized/eliminated system setup time in response to changing product requirements.Manufacturing planning and control system, on the other hand, follows hierarchical principles which are quite much reliant on the predicted information so to structure production and planning environment on it. Production system limitations, such as lack of adaptability in response to changing conditions, are in fact influencing the planning system to be structured on the predictions. The enhancements which are ensured by the architecture of EPS enable to relax the constraints on planning system which are imposed by the limitations of production system. These enhancements have an effect at different levels in the planning hierarchy. On the light of these improvements, the planning framework as it is used so far in the industry becomes invalid and this arise a requirement for planning system structure to be designed according to a fully reconfigurable system to be able to benefit such a production system by all means.This thesis targets to enlighten the relation between the production system characteristics and planning system structure by emphasizing the planning problems and proposing a planning reference architecture solution to be able achieve a responsive planning framework.
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| 3. |
- Bjelkemyr, Marcus, 1975-
(författare)
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System of Systems Characteristics in Production System Engineering
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This thesis presents a systems view of production, where production systems are compared and contrasted with other large and complex systems, commonly labeled System of Systems (SoS). The rationale for this approach lies in the evolution of production systems towards being holistic, sustainable, and agile; which increases the need for an improved understanding of both how internal system are interrelated, and how the production system interacts with its environment. In turn, this leads to an increase of complexity for the production system, which leads to new requirements on systems engineering.The definition of SoS is extensively discussed, and in this thesis formalized with regards to certain system characteristics that SoS exhibit. The presence of these characteristics is evaluated for three different levels of production systems to determine if they should be considered SoS. In the second part of the thesis, the SoS characteristics are addressed from an engineering point of view, i.e. if and how SoS properties are currently addressed in production systems engineering.Two main results are presented in this thesis: (1) production systems exhibit SoS characteristics; (2) SoS characteristics are not and cannot be addressed with current systems engineering methods. How SoS characteristics can be addressed is briefly discussed in the frame of reference.An additional purpose of this thesis is to initiate a new research area where production systems research and complex systems research are merged.
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| 4. |
- João, Dias Ferreira, 1986-
(författare)
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Bio-Inspired Self-Organisation in Evolvable Production Systems
- 2013
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The increasing market fluctuations and customized products demand have dramatically changed the focus of industry towards organizational sustainability and supply chain agility. Such critical changes in the strategic vision of the companies inevitably have a direct impact on the shop-floor operational requirements. In this sense, traditional shop-floor approaches are becoming increasingly inadequate leading to the adoption of more pluggable and reusable solutions.The emergence o modern manufacturing paradigms translates the effort undertaken by the academia in order to provide the required background to support the implementation of such distributed mechatronic systems. Biological systems, due to their similar distributed network-like structure, represent naturally a common analogy and source of inspiration for such distributed modular approaches. Hence, modern manufacturing paradigms usually rely on complexity science biologically inspired concepts to attain distributed control, adaptability, evolution, flexibility and robustness as core concepts. This originated the implementation of a number of different multi-agent based architectures. Nevertheless, with time the majority of the these implementation efforts left behind most of the bio-inspired concepts resulting in simple distributed approaches with considerable limitations regarding scalability, reconfigurability and distributed problem resolution. Particularly under the scope of Evolvable Production System (EPS) the implementation of self-organising mechanisms based on negotiation interaction protocols and dynamic coalition-based hierarchical complexity, have considerable hindered the system performance and limited the full exploitation of the paradigm potential.In this context, this licentiate thesis is focused on the development of a self-organising manufacturing systems that holistically mimics the main structural and regulatory principles followed by natural systems.For this purpose, the present approach was designed as opposed to the current tendency followed by modern productions approaches, in which the product holds the production knowledge and is responsible for the management of its own production. Instead, the production knowledge was reduced to the minimum and distributed over the manufacturing components. Self-organising principles heavily inspired on the regulatory mechanisms of biological systems, were then devised to regulate the critical control mechanisms of the manufacturing system. Hence, similarly to the natural world the characteristics and the system overall production emerge as consequence of the micro-dynamics of the systems. In this way, it becomes therefore possible to attain a system that is not only highly reconfigurable and scalable but also able to distributively tackle the manufacturing processes.Although the present work has been developed under the Evolvable Production System context, the introduced approach can be easily adapted to a wider range of modular networked-based systems.
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| 5. |
- Ribeiro, Luis
(författare)
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Diagnosis in evolvable production systems
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Esta tese aborda a problemática da execução de diagnóstico em instalações industriais complexas que são compostas por um elevado número de componentes que interagem entre si no âmbito do processo de produção.Apesar da abordagem apresentada ao problema ser geral e aplicável a várias classes de sistemas ligados em rede, o domínio dos Sistemas Evolutivos de Produção e os Sistemas Evolutions de Assembly (EPS/EAS) é utilizado como a base sobre a qual o sistema de diagnóstico proposto é implementado.Os Sistemas Evolutivos de Produção são um paradigma de produção recente e multidisciplinar cujo sistema de controlo é baseado em arquitecturas multiagente que denotam um elevado grau de desacoplamento entre os módulos que constituem o sistema. Esta é uma característica fundamental deste tipo de sistemas que garante uma elevada robustez e tolerância a falhas. Contudo, a tolerância a falhas, por si só não é suficiente para garantir o correcto funcionamento dos sistemas. Especialmente nos modernos paradigmas de produção os aspectos de monitorização e diagnóstico exercem uma acção regulatória fundamental. Contudo no sentido de não corromper a lógica de controlo que é altamente distribuída e que, desta forma, permite a fácil reconfiguração do sistema sem limites de escalablidade, abordagens como a proposta nesta tese são fundamentais.Neste contexto, o sistema proposto assume que a informação de diagnóstico proveniente dos métodos de diagnóstico existentes ao nível de cada um dos módulos do sistema deve ser harmonizada, transportada e considerada numa perspectiva de rede.Desta forma torna-se possível efectuar uma análise holística do problema de diagnóstico nomeadamente do sub-problema da propagação de falhas.Para não corromper a lógica de reconfiguração existente a abordagem proposta explora mecanismos de auto-organização e emergência ao nível de cada componente do sistema para fazer emergir o diagnóstico, focado nos aspectos da propagação de falhas, apenas explorando informação e interações locais entre os componentes.Assim garante-se a distribuição do sistema de diagnóstico, eliminando todo um conjunto de problemas associados a abordagem centralizadas (mais tradicionais) nomeadamente: escalabilidade, dependênia de um ponto único sujeito a falhas e os crescentes requisitos de performance computacional e complexidade algorítmica que acompanham a expansão do sistema.Neste contexto, o presente trabalho expõe toda a problemática associada aos sistemas referidos, mostrando estatisticamente a relevância de considerar os aspectos da propagação de falhas e sugere, com validação, uma solução concreta para os desafios apresentados.
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