485 research outputs found

    A holonic manufacturing architecture for line-less mobile assembly systems operations planning and control

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    Dissertação (mestrado) - Universidade Federal de Santa Catarina, Centro Tecnológico, Programa de Pós-Graduação em Engenharia de Automação e Sistemas, Florianópolis, 2022.O Line-Less Mobile Assembly Systems (LMAS) é um paradigma de fabricação que visa maximizar a resposta às tendências do mercado através de configurações adaptáveis de fábrica utilizando recursos de montagem móvel. Tais sistemas podem ser caracterizados como holonic manufacturing systems (HMS), cujas chamadas holonic control architecture (HCA) são recentemente retratadas como abordagens habilitadoras da Indústria 4.0 devido a suas relações de entidades temporárias (hierárquicas e/ou heterárquicas). Embora as estruturas de referência HCA como PROSA ou ADACOR/ADACOR² tenham sido muito discutidas na literatura, nenhuma delas pode ser aplicada diretamente ao contexto LMAS. Assim, esta dissertação visa responder à pergunta \"Como uma arquitetura de produção e sistema de controle LMAS precisa ser projetada?\" apresentando os modelos de projeto de arquitetura desenvolvidos de acordo com as etapas da metodologia para desenvolvimento de sistemas holônicos multi-agentes ANEMONA. A fase de análise da ANEMONA resulta em uma especificação do caso de uso, requisitos, objetivos do sistema, simplificações e suposições. A fase de projeto resulta nos modelos de organização, interação e agentes, seguido de uma breve análise de sua cobertura comportamental. O resultado da fase de implementação é um protótipo (realizado com o Robot Operation System) que implementa os modelos ANEMONA e uma ontologia LMAS, que reutiliza elementos de ontologias de referência do domínio de manufatura. A fim de testar o protótipo, um algoritmo para geração de dados para teste baseado na complexidade dos produtos e na flexibilidade do chão de fábrica é apresentado. A validação qualitativa dos modelos HCA é baseada em como o HCA proposto atende a critérios específicos para avaliar sistemas HCA. A validação é complementada por uma análise quantitativa considerando o comportamento dos modelos implementados durante a execução normal e a execução interrompida (e.g. equipamento defeituoso) em um ambiente simulado. A validação da execução normal concentra-se no desvio de tempo entre as agendas planejadas e executadas, o que provou ser em média irrelevante dentro do caso simulado considerando a ordem de magnitude das operações típicas demandadas. Posteriormente, durante a execução do caso interrompido, o sistema é testado sob a simulação de uma falha, onde duas estratégias são aplicadas, LOCAL\_FIX e REORGANIZATION, e seu resultado é comparado para decidir qual é a opção apropriada quando o objetivo é reduzir o tempo total de execução. Finalmente, é apresentada uma análise sobre a cobertura desta dissertação culminando em diretrizes que podem ser vistas como uma resposta possível (entre muitas outras) para a questão de pesquisa apresentada. Além disso, são apresentados pontos fortes e fracos dos modelos desenvolvidos, e possíveis melhorias e idéias para futuras contribuições para a implementação de sistemas de controle holônico para LMAS.Abstract: The Line-Less Mobile Assembly Systems (LMAS) is a manufacturing paradigm aiming to maximize responsiveness to market trends (product-individualization and ever-shortening product lifecycles) by adaptive factory configurations utilizing mobile assembly resources. Such responsive systems can be characterized as holonic manufacturing systems (HMS), whose so-called holonic control architectures (HCA) are recently portrayed as Industry 4.0-enabling approaches due to their mixed-hierarchical and -heterarchical temporary entity relationships. They are particularly suitable for distributed and flexible systems as the Line-Less Mobile Assembly or Matrix-Production, as they meet reconfigurability capabilities. Though HCA reference structures as PROSA or ADACOR/ADACOR² have been heavily discussed in the literature, neither can directly be applied to the LMAS context. Methodologies such as ANEMONA provide guidelines and best practices for the development of holonic multi-agent systems. Accordingly, this dissertation aims to answer the question \"How does an LMAS production and control system architecture need to be designed?\" presenting the architecture design models developed according to the steps of the ANEMONA methodology. The ANEMONA analysis phase results in a use case specification, requirements, system goals, simplifications, and assumptions. The design phase results in an LMAS architecture design consisting of the organization, interaction, and agent models followed by a brief analysis of its behavioral coverage. The implementation phase result is an LMAS ontology, which reuses elements from the widespread manufacturing domain ontologies MAnufacturing's Semantics Ontology (MASON) and Manufacturing Resource Capability Ontology (MaRCO) enriched with essential holonic concepts. The architecture approach and ontology are implemented using the Robot Operating System (ROS) robotic framework. In order to create test data sets validation, an algorithm for test generation based on the complexity of products and the shopfloor flexibility is presented considering a maximum number of operations per work station and the maximum number of simultaneous stations. The validation phase presents a two-folded validation: qualitative and quantitative. The qualitative validation of the HCA models is based on how the proposed HCA attends specific criteria for evaluating HCA systems (e.g., modularity, integrability, diagnosability, fault tolerance, distributability, developer training requirements). The validation is complemented by a quantitative analysis considering the behavior of the implemented models during the normal execution and disrupted execution (e.g.; defective equipment) in a simulated environment (in the form of a software prototype). The normal execution validation focuses on the time drift between the planned and executed schedules, which has proved to be irrelevant within the simulated case considering the order of magnitude of the typical demanded operations. Subsequently, during the disrupted case execution, the system is tested under the simulation of a failure, where two strategies are applied, LOCAL\_FIX and REORGANIZATION, and their outcome is compared to decide which one is the appropriate option when the goal is to reduce the overall execution time. Ultimately, it is presented an analysis about the coverage of this dissertation culminating into guidelines that can be seen as one possible answer (among many others) for the presented research question. Furthermore, strong and weak points of the developed models are presented, and possible improvements and ideas for future contributions towards the implementation of holonic control systems for LMAS

    Scheduling for Flexible Production: A Case Study of Production Leveling Under Volume Constraints

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    Flexible manufacturing systems in high-mix low-volume segments offer many challenges in terms of planning and scheduling. The complexity of these systems often requires a systemic approach for which humans are the perfect actors. However, computer systems can support scheduling tasks more effectively due to their capacity to synthesize large amounts of data. This paper describes a system developed for the flexible manufacturing of wooden doors with a wide range of product configurations. This paper proposes a rule-based scheduling method for high-mix production. The method was applied and validated at a wooden door producer. Based on the company's production schedule for a given week, a scheduling program was developed that suggested minor rearrangements for production leveling. As the rule-based approach makes the decisions verifiable, the program was validated at the producer, through a case study of production leveling under volume constraints. The results include the complete elimination of changeovers and the stabilization of throughput, which improved the precision of the delivery time. The producer is integrating the program into their production planning and control system. Thus, the results suggest that the proposed method can be useful for scheduling high-mix low-volume production, and merits further validation in similar environments.acceptedVersio

    Digital Twins: Review and Challenges

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    [EN] With the arises of Industry 4.0, numerous concepts have emerged; one of the main concepts is the digital twin (DT). DT is being widely used nowadays, however, as there are several uses in the existing literature; the understanding of the concept and its functioning can be diffuse. The main goal of this paper is to provide a review of the existing literature to clarify the concept, operation, and main characteristics of DT, to introduce the most current operating, communication, and usage trends related to this technology, and to present the performance of the synergy between DT and multi-agent system (MAS) technologies through a computer science approach.This work was partly supported by the Spanish Government (RTI2018-095390-B-C31)Juárez-Juárez, MG.; Botti, V.; Giret Boggino, AS. (2021). Digital Twins: Review and Challenges. Journal of Computing and Information Science in Engineering. 21(3):1-23. https://doi.org/10.1115/1.405024412321

    A Holonic Human Cyber-Physical System in Healthcare.

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    Mechanical and Mechatronic Engineerin

    An Architecture for the Integration of Human Workers into an Industry 4.0 Manufacturing Environment.

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    Thesis (PhD)--Stellenbosch University, 2021.ENGLISH SUMMARY: With the rise of Industry 4.0 and the development in technologies that contribute to this revolution in manufacturing, research has focused mainly on the machines and automated digital systems contributing to the manufacturing environment. Humans are still critical to manufacturing; offering unmatched ingenuity, robustness, and flexibility despite their apparent disadvantages in strength or precision. Many successful manufacturing firms still include humans in their manufacturing processes for these reasons, and it is critical that the integration of humans in an I4.0 manufacturing environment is given research attention. This dissertation first explores the requirements for the integration of human workers into an I4.0 environment. It was determined that the largest problem with human integration exists with data related to the human being digitised, managed, and communicated with other entities in processes that are identified as Administrative Logistics. It is identified that an administration shell similar to the RAMI4.0 administration shell concept is required to manage these Administrative Logistics on behalf of the human, and that a holonic systems approach is beneficial. The dissertation then proposes the concept of a Human Resource Holon Administration shell (HRH-AS). An architecture to implement such an administration shell is then developed, here named the BASE architecture. This administration shell facilitates the interfacing, data processing, and connectivity to other I4.0 components on behalf of the human, to aid in their integration to the digital factory environment around them. The BASE architecture addresses three identified responsibilities of such an administration shell, namely interfacing, digital data management, and delegation to other I4.0 components. BASE stands for Biography, Attributes, Schedule, and Execution, and is a time-based separation of concerns for key augmentations provided to the human worker. The BASE architecture separates value-adding and decision-making plugin components, which are specific to an application, from the core components, which are generic to any application. The BASE architecture led to the development of the 3SAL activity structure to facilitate the communication and management of industrial activities in a digital environment. With the help of an industry partner, two case studies were developed to evaluate an implementation of the BASE architecture. The company is an aerospace composites manufacturer and was chosen for the labour-intensive requirements of the composites industry. The case studies aimed to evaluate the architecture against the three identified administration shell responsibilities and determine if the human workers are elevated to resource holon status. The first case study aimed to show how BASE facilitates interfacing with humans in an I4.0 environment and also acted as a technology demonstrator for the second case study. The second case study evaluated the effect BASE had on the Administrative Logistics involved in the business processes workers were involved in. Together these case studies fully evaluate BASE’s ability to facilitate the integration of humans into an I4.0 manufacturing environment through identified responsibilities of the administration shell. The evaluation found that the BASE HRH-AS improves the effectiveness of Administrative Logistics of business processes the human workers were involved with, as well as opened new opportunities for decision making on the shop floor previously not possible. Value-adding, by means of the plug-in components of a BASE administration shell, has also been proven by the ability to do automated schedule management, automatic calculation of standard work and improved traceability using the 3SAL activity structure.AFRIKAANS OPSOMMING: Met die opkoms van Industrie 4.0 (I4.0) en die ontwikkeling in tegnologieë wat bydra tot hierdie revolusie in vervaardiging, het navorsing grotendeels gefokus op die masjiene en digitale stelsels wat tot die vervaardigingsomgewing bydra. Menslike werkers is steeds van kritieke belang vir vervaardiging, en bied ongeëwenaarde vindingrykheid, robuustheid en buigsaamheid, ondanks hul oënskynlike nadele in sterkte of noukeurigheid. Baie suksesvolle vervaardigingsondernemings sluit nogsteeds mense in hul vervaardigingsprosesse in om hierdie redes. Dit is dus noodsaaklik dat die integrasie van mense met 'n I4.0 vervaardigingsomgewing navorsingsaandag geniet. Hierdie verhandeling ondersoek eerstens die vereistes vir die integrasie van menslike werkers in 'n I4.0 omgewing. Daar word eerstens geïdentifiseer dat die grootste probleem met die integrasie van mense bestaan uit oneffektiewe prosesse wat data en informasie tussen mense en ander komponente in die vervaardigingsprosesse komminikeer, stoor en bestuur. Hierdie prosesse word na verwys as Administratiewe Logistieke. Daar word ook geïdentifiseer dat 'n administrasie-dop soortgelyk aan die RAMI4.0 administrasie-dop konsep benodig word om Administratiewe Logistieke te bestuur namens die mens, en dat 'n holoniese stelselbenadering voordelig is. Die verhandeling stel dan die konsep van 'n Human Resource Holon Administration Shell (HRH-AS) voor. Daarna word 'n argitektuur ontwikkel om so 'n administrasie-dop te implementeer, hier genoem die BASE argitektuur. Hierdie administrasie-dop vergemaklik die inskakeling, dataverwerking en konnektiwiteit met ander I4.0 komponente namens die mens. Die integrasie van die mens in die digitale fabrieksomgewing is dus bevoordeel. Die BASE argitektuur spreek drie geïdentifiseerde verantwoordelikhede van so 'n administrasie-dop aan, naamlik: koppelling met die mens, digitale databestuur, en delegering na ander I4.0 komponente namens die mens. BASE staan vir Biography, Attributes, Schedule en Execution, en is 'n tydgebaseerde skeiding van belange vir aanvullings wat aan die menslike werker verskaf word. Die BASE argitektuur skei waardetoevoeging- en besluitneming-inpropkomponente, wat spesifiek vir 'n toepassing is, van die kernkomponente, wat generies is vir enige toepassing. Die BASE argitektuur het gelei tot die ontwikkeling van die 3SAL aktiwiteitstruktuur om die kommunikasie en bestuur van industriële aktiwiteite in 'n digitale omgewing te vergemaklik. Met die hulp van 'n bedryfsvennoot is twee gevallestudies ontwikkel om 'n implementering van die BASE argitektuur te evalueer. Die maatskappy is 'n lugvaart saamgestelde-mater komponent vervaardiger en is gekies vir die arbeidsintensiewe vereistes van die saamgestelde-mater bedryf. Die gevallestudies was daarop gemik om die argitektuur teen die drie geïdentifiseerde verantwoordelikhede van die administrasiedop te evalueer en te bepaal of die menslike werkers verhoog word tot holon status. Die eerste gevallestudie se doel was om te wys hoe BASE n koppelvlak tussen mense en digitale stelsels toelaat. Die eerste gevallestudie was ook 'n demonstrasie dat 'n toepassing in die bedryfsvenoot se fabriek toegepas kon word vir die tweede gevallestudie. Die tweede gevallestudie het die effek geëvalueer wat BASE het op die Administratiewe Logistiek betrokke by die besigheidsprosesse waarby werkers betrokke was. Saam evalueer hierdie gevallestudies BASE se vermoë om die integrasie van mense in 'n I4.0 vervaardigingsomgewing te fasiliteer deur geïdentifiseerde verantwoordelikhede van die administrasiedop. Die evaluering het bevind dat die BASE HRH-AS die doeltreffendheid van Administratiewe Logistiek van besigheidsprosesse wat menslike werkers benut, asook nuwe geleenthede vir besluitneming op die winkelvloer, verbeter tot n mate wat voorheen nie moontlik was nie. Waarde-toevoeging, deur middel van die inpropkomponente van 'n BASE administrasie dop, is ook bewys deur die vermoë om outomatiese skedule-bestuur, outomatiese berekening van standaardwerk en verbeterde naspeurbaarheid met behulp van die 3SAL-aktiwiteitsstruktuur te doen.Doctora

    Festival and tradition in contemporary Florence

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    Certain sectors of the heritage and tourist industry argue that cities with art historical significance should be re-categorized as ‘museum cities’ because visitors intent on acquiring particular limited ‘consumer’ experiences outnumber the local population. Using the Feast Day of San Giovanni in Florence, Italy, as a focus this article questions this assumption. By evaluating the form of the fest day events and their relationship to the urban landscape, some of the historical conditions that have shaped the city are revealed. These conditions, understood as civic praxis, are accessible to everyone (to different degrees) and suggest Florence is anything but a museum

    Extending the BASE architecture for complex and reconfigurable cyber-physical systems using Holonic principles.

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    Thesis (MEng)--Stellenbosch University, 2021.ENGLISH ABSTRACT: ndustry 4.0 (I4.0) represents the newest technological revolution aimed at optimising industries using drivers such as Cyber-Physical Systems (CPSs), the Internet of Things (IoT) and many more. In the past two decades, the holonic paradigm has become a major driver of intelligent manufacturing systems, making it ideal to advance I4.0. The objective of this thesis is to extend an existing holonic reference architecture, the Biography-Attributes-Schedule-Execution (BASE) architecture, for complex and reconfigurable CPSs. In the context of this thesis, complex and reconfigurable systems are considered to be systems that are comprised of many diverse, autonomous and interacting entities, and of which the functionality, organization or size is expected to change over time. The thesis applies the principles of holonic systems to manage complexity and enhance reconfigurability of CPS applications. The BASE architecture is extended for two reasons: to enable it to integrate many diverse entities, and to enhance its reconfigurability. With regards to research on holonic systems, this thesis aims to address two important functions for systems implemented using holonic principles, namely cooperation and cyber-physical interfacing The most important extensions made to the architecture were to enable scalability, refine the cooperation between holons, and integrate cyber-physical interfacing services as Interface Holons. These extensions include platform management components (e.g. a service directory) and standardised plugins (e.g. cyber-physical interfacing plugins). The extended architecture was implemented on an educational sheep farm, because of the many heterogeneous resources (sheep, camps, sensors, humans, etc.) on the farm that need to be integrated into a BASE architecture implemented CPS. This case study implementation had to integrate data from different sensors, provide live analysis of observed data and, when required, notify the physical world of any problems in the CPS. At the end of the implementation, an evaluation was done using the requirements of a complex, reconfigurable CPS as evaluation criteria. This evaluation involved setting up quantitative and qualitative evaluation metrics for the evaluation criteria, doing the evaluations, and discussing what the results from the different evaluations indicate about the effectiveness and efficiency of the extensions made to the BASE architecture. The extensions made to the BASE architecture were found to improve robustness and resilience. The use of Erlang was found to play a very important role in the resulting reliability. The extensions also helped to fully address the original BASE architecture’s scalability shortcomings and to increase development productivity. Lastly, the extensions show the benefits of using service orientation to enable cooperation between holons and how extracting all cyber-physical interfacing of a system into dedicated Interface Holons reduces development time, improves reusability and enhances diagnosability of interfacing problems.AFRIKAANSE OPSOMMING: ndustrie 4.0 (I4.0) is die nuutste tegnologiese revolusie en dit is daarop gemik om industrieë te optimiseer deur middel van drywers soos Kuber-Fisiese Stelsels (KFSs), die Internet of Things (IoT) en vele meer. In die afgelope twee dekades het die holoniese paradigma ʼn belangrike drywer van intelligente vervaardigingstelsels geword, wat dit ideaal maak om I4.0 te bevorder. Die doel van hierdie tesis is om ‘n bestaande holoniese verwysings argitektuur, die Biography-Attributes-Schedule-Execution (BASE-) argitektuur, uit te brei vir komplekse, herkonfigureerbare KFSs. In die konteks van hierdie tesis, word komplekse en herkonfigureerbare stelsels gesien as stelsels wat bestaan uit menige diverse, outonome entiteite wat met mekaar interaksie het en waarvan die funksionaliteit, organisasie en grootte verwag is om te verander met verloop van tyd. Hierdie tesis pas die beginsels van holoniese stelsels toe om die kompleksiteit van KFSs te bestuur en om herkonfigureerbaarheid van KFSs te verbeter. Die BASE-argitektuur word uitgebrei om twee redes, naamlik om die integrasie van menige diverse entiteite te ondersteun en om die argitektuur se herkonfigureerbaarheid te verbeter. Die studie sal ‘n navorsingsbydrae lewer oor holoniese stelsels deur twee belangrike funksionaliteite van stelsels wat geïmplementeer is deur middel van holoniese stelsels aan te spreek – samewerking tussen holons en kuber-fisiese koppeling. Die belangrikste uitbreidings wat gemaak is aan die argitektuur was om skaleerbaarheid moontlik te maak, samewerking tussen holons te verfyn en om kuber-fisiese koppelingsdienste te integreer as holons. Hierdie uitbreidings sluit nuwe platformbestuurkomponente en gestandaardiseerde plugins in. Die uitgebreide argitektuur is geïmplementeer op ʼn opvoedkundige skaapplaas, omdat die skaapplaas baie heterogene hulpbronne (skape, kampe, sensors, mense, ens.) insluit wat in die BASE-argitektuur geïmplementeerde KFS geïntegreer kon word. v Hierdie gevallestudie-implementering moes data van verskillende sensors integreer, intydse analises doen van die waargeneemde data en wanneer nodig, ‘n entiteit in die fisiese wêreld inlig van enige probleme in die KFS. Aan die einde van die implementering is ʼn evaluering gedoen deur die vereistes van ʼn komplekse, herkonfigureerbare KFS as evalueringskriteria te gebruik. Die evaluering het bestaan uit die opstel van kwantitatiewe en kwalitatiewe evalueringsmaatreëls, die uitvoer van die evaluerings en ʼn bespreking van wat die evalueringsresultate aandui oor die effektiwiteit en doeltreffendheid van die uitbreidings wat aan die BASE- argitektuur gemaak is. Dit is bevind dat die uitbreidings wat gemaak is aan die BASE-argitektuur robuustheid en veerkragtigheid verbeter het. Die gebruik van Erlang het ʼn groot rol gespeel in die gevolglike betroubaarheid. Die uitbreidings aan die BASE- argitektuur het ook gehelp om die argitektuur volledig skaleerbaar te maak en om ontwikkelingsproduktiwiteit te verbeter. Laastens, bewys die uitbreidings die voordele van diensoriëntasie in die samewerking tussen holons en hoe die gebruik van Koppelings Holons (Interface Holons) ontwikkelingstyd verminder, die herbruikbaarheid van programbronkode verbeter en diagnoseerbaarheid van koppelingsprobleme versterk.Master

    Literary Cultures in/and Italian Studies

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    The article opens by considering how contemporary Italian Studies scholarship is situated in relation to the long-standing dominance of literary culture as a major disciplinary concern, and the persistence of traditionally conceived canons, questions, and methods. The authors discuss how the scope of literary research has expanded in recent years and become more enmeshed with sociological, political, and ideological enquiry. They review how previous definitions of literary cultures and practices have been refreshed with new theoretical and interdisciplinary approaches, and through transnational dialogues and collaborative modes of research. A diachronic survey discusses key innovations both in the study of canonical or ‘high culture’ literary phenomena – such as Dante, Leopardi, or Futurism –, and in engagements with previously overlooked writing in popular genres or media, or by socially marginalised authors. It concludes by reflecting on how literary studies is both critiqued and defended within current debates over the standing of humanities research within and beyond the academy

    Architettura e Realismo. Programma

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    Il convegno "«Uno spazio reale adeguato»: architettura e realismo", la giornata di studi e mostra "«Il sempre teorizzar nulla rileva...»: nuovo realismo e architettura della città", il convegno "Per una nozione operativa di realismo: espressione critica e impegno civile e la mostra Il realismo nella didattica del progetto: Torino Napoli Milano", uniti sotto il titolo comune di Architettura e realismo sono promossi da un gruppo di lavoro costituito da giovani ricercatori e docenti delle facoltà di Architettura di Torino, Milano e Napoli, a partire dalla avvertita esigenza di aggiornare la riflessione sulla architettura come pratica costruttiva e sulla città come luogo per eccellenza della vita dell'uomo a partire da una analisi critica di quanto si è prodotto negli ultimi decenni. Da un lato grandi architetture spettacolari che rispondono alle logiche del mercato e della comunicazione e, dall'altro - in una sorta di inspiegabile paradosso - la de- regolazione della città diffusa priva di struttura, elementi riconoscibili e spazio pubblico. In entrambi i casi, pur nella loro diversità, si è prodotto un pericoloso distacco della architettura dal suo obiettivo ultimo: conformare lo spazio fisico dei manufatti e della città, del territorio e del paesaggio, per determinare in maniera consistente lo scenario della vita dell'uomo, nella sua dimensione, innanzitutto, collettiv
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