1,721,088 research outputs found
Comparison of new metaheuristics, for the solution of an integrated jobs-maintenance scheduling problem
Full text linkThis paper presents and compares new metaheuristics to solve an integrated jobs-maintenance scheduling problem, on a single machine subjected to aging and failures. The problem, introduced by Zammori et al. (2014), was originally solved using the Modified Harmony Search (MHS) metaheuristic. However, an extensive numerical analysis brought to light some structural limits of the MHS, as the analysis revealed that the MHS is outperformed by the simpler Simulated Annealing by Ishibuchi et al. (1995). Aiming to solve the problem in a more effective way, we integrated the MHS with local minima escaping procedures and we also developed a new Cuckoo Search metaheuristic, based on an innovative Levy Flight. A thorough comparison confirmed the superiority of the newly developed Cuckoo Search, which is capable to find better solutions in a smaller amount of time. This an important result, both for academics and practitioners, since the integrated job-maintenance scheduling problem has a high operational relevance, but it is known to be extremely hard to be solved, especially in a reasonable amount of time. Also, the developed Cuckoo Search has been designed in an extremely flexible way and it can be easily readapted and applied to a wide range of combinatorial problems. (C) 2018 Elsevier Ltd. All rights reserved
Exploiting Machine Learning and Industry 4.0 traceability technologies to re-engineering the seasoning process of traditional Parma’s Ham
No full textThe work presents a Machine Learning approach for predicting the quality of the curing process of Parma ham, combined with a study of business process re-engineering, based on RFID and Deep Learning technologies for automatic recognition and tracking of the hams along the curing process. Quality management has proven to be crucial for efficient and effective processes, even more so for the food industry, both for commercial and regulatory purposes. This is even more evident in artisanal-based processes, such as the one concerning traditional Prosciutto di Parma seasoning. The work proposes and compares a Feed-Forward Neural Network and a Random Forest for predicting the distribution of the number of hams by commercial quality class of a given aging lot. Such a prediction, based on origin, process, and curing data, can provide early indications of process output, enabling strategic commercial competitive advantages. The importance of the genetic component in the determination of the final quality is also evaluated, as it is considered one of the most influential external variables. Moreover, following the AS-IS description of the current process, a redesign is proposed, to enable data collection and tracking of individual ham in order to propose a future precision prediction system that would allow even finer control of the process
The analytic hierarchy and network processes: Applications to the US presidential election and to the market share of ski equipment in Italy
No full textBeyond serving in complex decision-making, both the Analytic Hierarchy Process (AHP) and the Analytic Network Process (ANP) for the measurement of both tangibles and intangibles can be used in prediction rather effectively. This paper examines the potential of these models to help one discern current states and situations as well as suggest future outcomes. The first example uses the AHP to predict the Democratic Nominee in the 2008 United States presidential election and then uses that information to predict the overall election winner. The second example uses the ANP to predict the market share for ski equipment. The general structure of these models can be applied in many and diverse situations
Fuzzy Overall Equipment Effectiveness (FOEE): capturing performance fluctuations through LR Fuzzy numbers
Full text linkThe paper focuses on the Overall Equipment Effectiveness (OEE), a performance indicator that is extensively used in the
industry. The aim is to extend the capabilities of the OEE, so as to capture the day-to-day fluctuations to which manufacturing
performances are subjected. To this aim, manufacturing losses are decomposed into elementary causes and
modelled as LR fuzzy numbers. Next, in order to compute the Fuzzy Overall Equipment Effectiveness (FOEE), single
losses are aggregated using the ‘fuzzy transformation model’. This approach limits the fuzzy overestimation phenomenon
and assures both results’ accuracy and robustness. An industrial application, part of a lean project carried on by an
important Italian manufacturing firm, is finally presented. Results are encouraging, since the FOEE made it possible to
trace back the share of the overall fluctuations that is ascribable to each cause of loss. In this way, it provided the basis
for setting improvement priorities and directed the lean team toward the selection of appropriate corrective actions
A Conceptual Framework for Project Scheduling with Multi-Skilled Resources
Full text linkThe success of a project depends, mostly, on the ability to create multi-skilled teams and to assign them to project's tasks, without creating multi-tasking and over-allocation. In this respect, the Multi-skilled Work Force Scheduling Problem has attracted a great interest, both for academicals and practitioners. Unfortunately, most of the academic works produced so far, has not yet found its way into practice, mainly because of a complex and rigid mathematical formulation, which poses a serious constraint on the precision of the input data. To solve this criticality, we abandon the over optimistic idea of a global optimum and we propose a hierarchical framework that extends the well-known Dynamic Scheduling approach. The focus is on the resource assignment phase, with the objective to allocate multi-skilled resources in a quasi-optimal way, so as to assure project quality and a harmonious development of the workforce
Utilizzo del modulo MRP per la pianificazione della produzione nel caso di forniture in “Consignment Stock”
No full textANP/RPN: a multi criteria evaluation of the risk priority number
No full textThis paper presents an advanced version of the failure mode effects and criticality analysis (FMECA), whose capabilities
are enhanced; in that the criticality assessment takes into account possible interactions among the principal causes of
failure. This is obtained by integrating FMECA and Analytic Network Process, a multi-criteria decision making technique.
Severity, Occurrence and Detectability are split into sub-criteria and arranged in a hybrid (hierarchy/network) decisionstructure
that, at the lowest level, contains the causes of failure. Starting from this decision-structure, the Risk Priority
Number is computed making pairwise comparisons, so that qualitative judgements and reliable quantitative data can
be easily included in the analysis, without using vague and unreliable linguistic conversion tables. Pairwise comparison
also facilitates the effort of the design/maintenance team, since it is easier to place comparative rather than absolute
judgments, to quantify the importance of the causes of failure. In order to clarify and to make evident the rational
of the final results, a graphical tool, similar to the House of Quality, is also presented. At the end of the paper, a
case study, which confirms the quality of the approach and shows its capability to perform robust and comprehensive
criticality analyses, is reported
Utilizzo del modulo MRP per la pianificazione della produzione nel caso di forniture in Consignment Stock
No full textIl Consignment Stock è una metodologia di integrazione logistica mirante alla minimizzazione delle scorte in ottica di filiera, basata su una stretta collaborazione e su un regolare scambio informativo fra le aziende coinvolte. Considerando il crescente interesse che il Consignment Stock sta generando in campo industriale, l'obiettivo di questo lavoro consiste nell'individuazione e nella formalizzazione dei fattori che determinano il successo di tale strategia. La parte centrale del lavoro consiste nell'ideazione di una modifica di carattere operativo, da apportare al modulo MRP standard, per consentire un più semplice e performante gestione della produzione nel caso di forniture in Consignment Stock. A chiarimento del metodo proposto, viene infine proposto un esempio numerico a carattere illustrativo
Potential for Cogeneration Through Solar Energy in the Tissue Industry: Technical and Economic Aspects
No full textThis paper investigates the feasibility of a solar cogeneration system, as a solution to reduce fossil fuel consumption and greenhouse gas emissions in a tissue mill, located in the industrial district of Lucca (North Italy). Although the paper sector has a high theoretical potential for the use of solar energy, the implementation of a solar thermal plant may not be economically sustainable, due to the expensive investment of such a system and to the uncertainty of future benefits. These issues are even more relevant in a moderate climate, where the high variability of the direct normal irradiance can prevent the technical feasibility of the plant. To demonstrate the possible use of solar energy in paper mills, a concentrating solar power plant with thermal storage, based on parabolic trough technology, has been chosen as a feasible solution for combined heat and power generation and its technical and economical performances have been evaluated through an extensive simulation analysis. The results obtained prove the feasibility of the proposed system and assure a good economic profitability. Results also show how the possibility of benefiting from economic incentives for renewable electric power generation is fundamental to reduce the payback period and to assure the profitability of the investment
A Conceptual Framework for Project Scheduling with Multi-Skilled Resources
No full textThe success of a project depends, mostly, on the ability to create multi-skilled teams and to assign them to project's tasks, without creating multi-tasking and over-allocation. In this respect, the Multi-skilled Work Force Scheduling Problem has attracted a great interest, both for academicals and practitioners. Unfortunately, most of the academic works produced so far, has not yet found its way into practice, mainly because of a complex and rigid mathematical formulation, which poses a serious constraint on the precision of the input data. To solve this criticality, we abandon the over optimistic idea of a global optimum and we propose a hierarchical framework that extends the well-known Dynamic Scheduling approach. The focus is on the resource assignment phase, with the objective to allocate multi-skilled resources in a quasi-optimal way, so as to assure project quality and a harmonious development of the workforce
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