1,721,257 research outputs found
Discovery and digital model generation for manufacturing systems with assembly operations
No full textIndustry 4.0 determined the emergence of technologies which allow for data-based production planning and control approaches. Digital twins can be used to take decisions based on the current system state. Hence, their performance strictly depends on the capability to correctly represent their physical counterparts at any time. The development of digital twins for manufacturing systems can be significantly accelerated by automated model generation techniques. However, production systems including assembly stations suffer from event records with multiple part identifiers, resulting in the wrong finding of the system structure. In this paper, we define the problem of the proper discovery of assembly operations. Then, we describe an algorithm to generate a complete digital model exploiting the new concept of object-centric process mining. In a case study, a flow shop including assembly stations is successfully discovered, allowing for the automated building of a simulation model with the proper logical behavior
An Introduction to Digital Twins
No full textThis work presents an introduction to digital twins, digital versions of real objects designed to aid in analysis, enhancements, and decision-making. Its main goal is to introduce what digital twins are, highlighting their key characteristics, their role in supporting real-world counterparts, and the models they employ
La VAS dei piani che prevedono la realizzazione di un porto turistico: il caso del Piano Urbanistico del comune di Tertenia.
No full textLa VAS è orientata a valutare che l’effetto delle azioni di un piano territoriale vengano considerate durante l’elaborazione e prima dell’adozione dello stesso. Sarebbe opportuno definire un quadro logico che integri i risultati dell’analisi della coerenza con il quadro pianificatorio in atto, dell’analisi ambientale e del piano, in un unico sistema di obiettivi, in cui questi definiscano una cornice complessiva basata su correlazioni concettuali. L’individuazione degli impatti, positivi e/o negativi, delle azioni, riferite alla tutela delle risorse ambientali e al paradigma dello sviluppo sostenibile, costituisce il fulcro della VAS. Con queste premesse, il saggio analizza la VAS del Piano urbanistico del Comune di Tertenia, con l’obiettivo di valutarne l’efficienza in termini di individuazione dei possibili impatti derivanti dalla realizzazione di un nuovo porto turistico, riconosciuta nel piano quale azione trainante lo sviluppo economico territoriale
Automated digital twin generation of manufacturing systems with complex material flows: graph model completion
Full text linkIndustry 4.0 determined the emergence of technologies that enable data-driven production planning and control approaches. A digital model can be used to make decisions based on the current state of a manufacturing system, and its efficacy strictly depends on the capability to correctly represent the physical counterpart at any time. Automated model generation techniques such as process mining can significantly accelerate the development of digital twins for manufacturing systems. However, complex production environments are characterized by the convergence of different material and information flows. The corresponding data logs present multiple part identifiers, resulting in the wrong finding of the system structure with traditional process mining techniques. This paper describes the problem of discovering manufacturing systems with complex material flows, such as assembly lines. An algorithm is proposed for the proper digital model generation, aided by the new concept of object-centric process mining. The proposed approach has been applied successfully to two test cases and a real manufacturing system. The results show the applicability of the proposed technique to realistic settings
Models and algorithms for throughput improvement problem of serial production lines via downtime reduction
Full text linkThroughput is one of the key performance indicators for manufacturing systems, and its improvement remains an interesting topic in both industrial and academic fields. One way to achieve improvement is to reduce the downtime of unreliable machines. Along this direction, it is natural to pose questions about the optimal allocation of improvement effort to a set of machines and failure modes. This article develops mixed-integer linear programming models to improve system throughput by reducing downtime in the case of multi-stage serial lines. The models take samples of processing time, uptime and downtime as input, generated from random distributions or collected from real system. To improve computational efficiency while guaranteeing the exact optimality of the solution, algorithms based on Benders Decomposition and discrete-event relationships of serial lines are proposed. Numerical cases show that the solution approach can significantly improve efficiency. The proposed modeling and algorithm is applied to throughput improvement of various systems, including a long line and a multi-failure system, and also to the downtime bottleneck detection problem. Comparison with state-of-the-art approaches shows the effectiveness of the approach. Supplementary materials are available for this article. Go to the publisher’s online edition of IISE Transactions
Mathematical programming formulations for approximate simulation and optimization of closed-loop systems
No full textCarta de José Caciro Da Matta a Pedro Dorado Montero
No full textCarta del profesor portugués, D. José Caciro da Matta, a D. Pedro Dorado Montero, rogándole le ayude en alguna de sus obras
Carta de José Caciro Da Matta a Pedro Dorado Montero
No full textCarta del profesor portugués, D. José Caciro da Matta, a D. Pedro Dorado Montero, agradeciéndole el ofrecimiento de varios libros y comunicándole el envío de uno suyo
Automated digital twins generation for manufacturing systems: A case study
Full text linkThe recent industrial scenario was defined by the emergence of digital twins and cyber physical systems as key elements for manufacturers leadership. Digital models can perform good in terms of production planning and control decisions if they are correctly representing their physical counterparts at anytime. Discrete event simulation can be considered as established digital models of manufacturing system, thanks to the proven capabilities of correctly estimating the system performances. Automated simulation model generation techniques can significantly reduce model development phases and allow for using simulation models for short term decisions in production. Application studies and test cases are scarce in the literature. In this paper, we present the application of a digital model generation method. The test case is done exploiting a lab-scale model of a manufacturing system composed by six stations. We investigate how the model generation works online, during the transient phase of a manufacturing system. Results confirm the real-time applicability of the approach provided that sufficient data points are available from the production event logs
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