1,721,023 research outputs found
Pseudo-fuzzy discrete-event simulation for on-line production control
No full textIn this paper we propose an alternative use of commercial object-oriented discrete-event simulators. We attempt to bridge the intrinsic inaccuracy of simulators in modelling real systems affected by fuzziness. The strategy adopted, called pseudo-fuzzy discrete event simulation, models fuzziness through a set of several classic simulation runs to trace an output fuzzy performance function. The idea behind the approach proposed is to use the simulator as a fuzzy operator, which embeds some stochastic functions. A benchmark industrial setting has been used to build a reference simulation model and perform evaluations of the simulation strategy proposed for a specific working cas
Enterprise modelling for networked enterprise: Interaction aspects for a training organization
No full textThis paper focuses on enterprise models representing interaction aspects which are very important when modelling networked enterprises. To this aim, a case study concerning an Italian training organization is addressed as a show case, where a re-engineering of the quality management systems where addressed. The main criticalities of cooperation either in the real operative practice and in the related modelling approach are presented. Several interaction requirements at different EM levels and the main factors to be considered in design modelling are also discussed
The interoperability of exergy and Life Cycle Thinking in assessing manufacturing sustainability: A review of hybrid approaches
No full textToday, the Life Cycle Assessment (LCA) is the most employed tool for assessing the sustainability of products and processes, both from an environmental, social and economic point of view. Exergy is defined by literature as the amount of useful work that can be derived from a real system when it is brought into equilibrium with its environment. In the literature, it is considered an outstanding concept that can be applied to enhance the effectiveness of ordinary evaluation models such as LCA. The literature proposes a variety of hybrid approaches that combine Exergetic Analysis (EA) and LCA with different combination frameworks. The aim of this paper is to describe the potential of each hybrid method and to characterize the degree of interoperability between EA and LCA that each of them can provide. Nevertheless, there are drawbacks that seem to be too challenging to overcome: a variety of inconsistencies in the interpretation of the results due to the difficulty of the inventory phase and the ambiguity in the choice of the correct alternative in the standard databases; the link with old techniques that refers to obsolete approaches in finding data that suit to the updated goals and scopes; the difficulty in conducting an assessment affected by the least possible uncertainty. Following a theoretical overview of the principles of each hybrid method that binds EA and LCA, the authors want to provide a review from a completely different point of view than the state-of-the-art literature, on how effectively EA and LCA can interact with each other in order to provide a more holistic view of the system/process to be assessed. The fascinating circumstance that emerges from the review is that any exergy approach would be more effective if joined (not replaced) to the standard LCA, because it turned out to be complementary. This theory has long been developed by many authors in their case studies as a confirmation of what Gutowski wrote years ago: no single alternative criteria or subsidiary model, independently of how well aggregated, may offer a suitable answer for all conditions. Specifically, through this review, the practitioners would be able to choose the best suited hybrid methodology, according to their aims, join the outcomes together and achieve a transdisciplinary knowledge of the behavior of the study case system, in order to design the best improvement strategies
On-line Production Control via Discrete Event Simulation: an Industrial Application
No full textA different perspective on the use of discrete event simulation is proposed to respond on-line to daily practical production-control problems. A simulation model has been designed and implemented, for a real manufacturing system, with the aim of supporting real-time operative decisions concerning contingencies in production control. Two benchmarking cases of applications have been addressed, with the flow production environment running in a clearly transient condition. The applications provide some interesting insights into future development of the application
Use of High Level Architecture and Virtual Reality for Technological Distributed Simulation in Manufacturing
No full textThe use of three-dimensional Finite Element Simulation Analysis in Optimizing Processing Sequence of Synergic MIG Welding for Robotic Welding System
No full textInternal logistics integration by automated storage and retrieval systems: A reengineering case study
No full textNowadays, factors like globalization, productivity, and reduction of time-to-market make the impact of logistics on production by far wider than in the past. Such a complex scenario originated considerable interest for the design, planning and control of warehousing systems as new research topics (De Koster et al. 2007). However, in spite of the importance of warehouse design and management, authors agree on the lack of systematic approaches (Baker and Canessa, 2009). Moreover, the existing contributions do not typically consider the problem of warehouse design in a continuous improvement context. On the contrary, with the enhanced customer demand, for most manufacturing industries it has become increasingly important to continuously monitor and progress the internal logistics. This paper presents a preliminary study for the reengineering of the logistics in a Southern Italy firm producing shoes and accessories based on formal modeling. We address a widely used solution for warehouse material handling, i.e., Automated Storage and Retrieval Systems (AS/RSs) (Dotoli and Fanti 2007). These systems are a combination of automatic material handling and storage/retrieval equipments characterized by high accuracy and speed. In order to reengineer the logistic system, a Unified Modelling Language (UML) (Miles and Hamilton, 2006) model is adopted (Dassisti, 2003). © 2012 Springer-Verlag
Guidelines for implementing augmented reality procedures in assisting assembly operations
No full textA layout-analysis based system for document image retrieval
No full textThis paper presents new system for document image retrieval, based on layout-analysis. The system, that is well suited for commercial form retrieval, uses Radon Transform for layout description and Dynamic Time Warping for document image matching. The experimental results, that were conducted using real and simulated data sets, demonstrate the proposed approach is effective and robust with respect to different classes of commercial forms and shifted/rotated document images
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